EDIT: I copied this post out of this threadGifts for challenged people and think it's time to bump this thought again. It's coming up on fall, check your house and your family's houses! I'm listening to my mom tell my aunt about visiting an elderly aunt, and how much things could use to be changed so the lady can see things, not fall, etc. A lot of obvious hazards, IF you look, and no one looks at it thinking this way. Reminded me to dig this up.
Expanding on the lights and visibility for older folks thoughts:
I'm gonna use your grandma as an example, and am thinking about several old ladies I know as I write this, change details as needed for your own situation. I'm also thinking about the modifications I made to the rental we are in for my mom.
Eyes dim as you get older, and older houses do not have a lot of fixtures to start with. Cataracts, glaucoma and macular degeneration make it even worse. Walk into your grandma's house with dark sunglasses on, and look around the house. That's quite probably what she is seeing. What can be changed here?
Some places to check: porches, around the doors, the kitchen, the bathrooms, hallways, steps, wherever meds are kept, anyplace that they spend a lot of time (like their favorite chair.)
Steps need to be visible. The rental we are in has wood steps, I put strips of bright yellowish green duct tape on the edge of each step. It will come off easily when we move out, and although those steps are horrible and we go up and down them many times a day, neither of us has fallen. They sell systems to do this, but bright duct tape is pretty effective.
Ideal would be to make the sun come in more. It's difficult if you don't move well to open and close blinds or drapes though. And windows always need washing, and probably vegetation needs trimming back. Consider that, if it can be done. Don't install anything that has to be dealt with several times a day, like blinds etc, or that takes maintenance, unless YOU are willing to do it for them from now on. See if anything can be changed there though. Trim the bushes if it's needed.
Dark walls don't bounce much light around, we are in a rental I'm am NOT going to repaint. I DID thumbtack neatly done white sheets to the walls in mom's room (to cover blood red walls, that were painted badly, and need either another 2 coats of blood red to look at least competently painted, or several serious layers of Killz to eliminate that mess.) It lightened the room up quite a bit, I then put some purple striped Mexican blankets diagonally over it for decor, anything like pictures etc work well, just something to hide the sheets. That exact idea might not work for you, it is just what worked for us in a rental to lighten up dark (and horrible) walls. The idea is to look and see if dark walls can be lightened with paint or something else. Big pictures would work too, or a bunch of smaller ones, especially if they are behind glass, so the light reflects.
LED lights are not the best for the environment, but they are cheap to run, and I bet part of the reason the bulbs in grandma's house are low wattage is to avoid high electric bills. LEDs (and most other bulbs) come in different color ranges
I classify them (and label each bulb with sharpie) by yellow based (the left side of that scale) blue based (the middle of that scale) or daylight (right end of the scale.) The left end lights are softer, more friendly looking, but if you are having issues with sight, the daylight spectrum bulbs are fantastic. They light an area incredibly well. The mid section, blue based ones, are kind of in between, I use those for what most people would use the softer toned bulbs for, and daylights every where else. (Incidentally, florescent bulbs come in daylight too. A 4 ft light fixture in a kitchen or basement gets a serious personality change by putting daylight spectrum bulbs in it!) Swapping out normal bulbs for daylight spectrum bulbs will make an immense difference. (I use LED's in the rental so I don't have heat issues in summer, in our home we are putting in switch marked winter and summer fixtures, that will have LED for summer, and incandescent or halogen for winter, to add heat, but that's not practical for most people. In winter we'll mostly use lights with a red switch, in summer you mostly use lights with a blue switch.) Incidentally, I have been running LEDs since they became affordable, about 2010, and have yet to have to throw one away. I also recently found online 14 watt LED bulbs. oooh, those are bright! Makes a lamp way more effective!
Properly (and safely!) hard wiring light fixtures though walls and ceilings is not a job that can be done casually. What can be done casually is add small fixtures that have cords. Look for "under cabinet lighting" you can get them in LED or florescent (I'm unsure about incandescent) with batteries, plugs, or hard wired. Looking at the actual lighting needs of the person and house, and figuring out where light needs to be and what's available for power before going fixture shopping is wise. They can be put a lot of neat places, like dark hallways, or closets also. A trick I use for switched hall lights when I don't want to mess with the fixture is the things that screw into a bulb socket that makes a plug outlet, then run plug wired lights off of it, so they work off the switch. They look like this and are at most hardware stores.
Another trick I use for lighting is timers that turn lights on automatically. We use all the natural window lighting we can, but I have good bright lights on timers, set to come on 1/2 hour before dark, and stay on till the time we go to bed. (Don't forget to adjust them as the season changes!) Especially in winter, they are wonderful. We don't tend to notice it's getting dark and get up to turn on a light until its IS dark, then you are looking for light switches in bad visibility, and that's when falls happen. A cat or dog runs under your feet when you don't see them, and it can be very bad. It's also great to go to bed with good lighting, and know it'll shut itself off. Turning off the lights as you go to bed is a dark trip hazard. Hall lights on timers might be excellent.
Check for trip hazards in general. Black Gorilla tape is my favorite for that, I tape everything down. Any adhesive on floors etc you need off removes easily with goo gone or orange oil or orange degreaser. Duct tape is less adhesive, and peels up on the edges much faster. If you put any tape down in an older person's house, check it every few months for peeling, Gorilla black won't need replacing for several years, but I'd check it anyway. What can be moved for trip hazard mitigation? What can be marked? What can be taped down? What can be eliminated? Look around, in your dark glasses. and see what is a potential problem.
It's hard sometimes when you are young to realize that as most people's eyes age, they don't pick up light as easily, the dark glasses in the house trick is REALLY useful for figuring out what might need better lighting, as well as asking a lot of questions. This isn't the kind of project you do as a surprise for someone, it's one you do as team project, them telling you what bugs them, as well as you asking "what about here?" and then you figuring out how to change it. If you want to do it as a gift, I'd suggest the gift they open is a box of daylight LED's, and a certificate promising to change the lighting in the house. I have yet to see one set of daylight bulbs not convince people how much difference it makes. Be sure to mention they are cheaper to run!
And one last random thought: Need extra money? Business opportunity here! Get other people to pay you to do this for their relatives. Someone's child in another state might pay well to know it's been done.