Your raised beds look great. I'm sure your Mother will be happy with their performance. And kudos to you for helping her find a way to continue her garden in comfort!
I have hugelkultures that I built on grade (no digg) and they are performing VERY well. We've had record rainfall in my area of Michigan (more than 12 inches in April alone) and they've helped keep my high
water table in check.
My
project is not quite one year old. It is planted with strawberries as a ground cover, garlic, thyme, oregano, lavender and other yummy stuff. I'm testing out how well melons and pumpkins will fair in the culture without additional water inputs. Happily, I haven't had to drag a hose out all year... even when temps went into an unseasonal 90+ degrees for a few days. With my current weather patterns, I'm happy to report a truly living soil...
mushrooms started popping-up and that sure puts a smile on my face.
Continued good luck and Joy in the garden!