My dad could no longer operate a CD player or iPod. But he could use the music player that I designed and made for him, because it operates like a familiar two-knob radio. I was inspired to make this by the documentary Alive Inside which shows the profound joy felt by some people with dementia when listening to their favorite music.
It is easy to make one — good project for kids! I went through several revisions, making it simpler each time. Everything I did (e.g. software, wood case design) is open source. You can order the parts online from Amazon etc. for ~$95, including the pre-cut pieces for the wood case. No soldering. A 13 year old can probably do this with minimal assistance. Younger kids with more assistance.
Testimonial: I recently assembled a dqmusicbox per your instructions – and it just . worked. Yesterday I turned over my incarnation of the box to my father. It has been a long time since I saw such an emotional reaction from him. I let him at it without explanations at all, and he made it work without instructions. He could not help me much naming songs and music he would like for the box, so I went from my own memory of what he enjoyed listening to. Some of his favorites triggered immediate responses – I should have filmed it. — Ketil
UPDATE: DQMusicBox is a 2017 Hackaday Prize finalist! I entered to get more people to make one.