Ask HN: Music tech for special needs users

I am involved with music studios at several places in England, UK. A new client wants to learn to DJ but also happens to be in a wheelchair, with no use of legs, arms, and communicates by rocking their headrest to move a cursor on a tablet. They can also suck. That's it. Full mental faculties are intact.

I've just begun to research assisted tech, but I would like to hear from anyone with severely restricted movement that DJ's or manages to create electronic music, for fun or professionally.