Best workout for 66 y/o mother with arthritis? (ABSOLUTE beginner)

Hi all

My mother has been retired for a year. She used to be a cleaner and was always pretty fit and physical, but since retiring all she does exercise-wise is go on walks. Her posture is pretty poor from so many years of cleaning and being bent-over, that she has developed arthritis in her neck and knees.

This morning my husband and I were teasing her, saying she should get into weights. I even gave her my 1kg weights to try and do a compound bicep-curl to shoulder-press to see if she could do it! Lol. She did it, but struggled. She has virtually no strength or flexibility, but has a tiny frame (5'0", 100lbs soaking wet) and has hardly a square inch of fat anywhere on her. In fact her problem is that she could be knocked over by a gust of wind!

I think she could really benefit from doing some FitnessBlender videos with me, but I don't know which one to try her on first. I quite happily do level 4 and 5 FB vids, but she's obviously only up to a level 1 or 2. Anything down on the ground is out because of her knees. Any suggestions, guys?