I asked my wife about craft life beyond arthritis. Her fingers are getting stiff but she isn’t suffering yet. She is one of the younger of the groups she attends so she knows people with various problems with their dexterity.. Mind you the person I went in for has arthritus that means she is no longer enjoying her knitting. I thought crochet might be something for her but no idea what it is or needed so looks like plan C for that person.
She suggested circular knitting needles to take the weight of the knitting in the lap and to minimise changes.
She also does different things in a night. She couldn’t crochet for several months but she could knit. She did knitting and embroidery (and a bit of quilting needle work) to keep going. Then after half a year she tried crochet again and managed it. Tell your friend not to give up.
She also knows lace makers who can no longer knit. It’s easier on the fingers but a big learning curve for someone new to it.