Ellen, apparently, I got your butt, in addition to what I needed for my own, and though I'm on the high extreme of what's supposed to be 'petite' (5'4"), my legs are slightly longer than what's considered proportional, for my height. So, I typically need average, and sometimes even tall cuts, but John has very short legs, and struggles with finding jeans with a short enough inseam - and won't let me hem them. So, when I see him struggling with the hem torn, and trying to put his feet through the holes it creates, I just cut them off to just a hair above where the damage is. Still not allowed to hem them (I truly have no idea why), but the edges only fray a little, when I use the pinking shears, and it looks intentional, after a few washes - and they stop catching on everything, including his toes, lol.
I'll probably post a picture later, but I used this material to extend the length on some denim shorts. I am pretty sure no one would guess they didn't originally have this. Both sides of the material are equally nice just different shades of blue.
I'm not going for invisibility. I thought I'd play with sashiko or something a little.
I was thinking along the same lines as your suggestion of sewing a patch wrapped around the bottom of the leg, sewn inside and out. I guess if it's not too thick for your husband to use, I may as well give it a try.