Non slip grab rail recommendations please!

Hi everyone,
I'm in the process of sorting out a bathroom for my son, who is 14 with SLD and complex health needs. What I'm stuck on at the moment is grab rails. He is very unsteady and obviously in a bathroom he might have wet hands, so can anyone recommend a brand or specific handrail that works well (or tell me if there are ones I should avoid at all costs!). A lot seem to be shiny plastic or chrome, and surely his hand would just slip and he'd be on the floor?

My thinking is probably a 135° one for him to haul himself off the toilet with, and a straight one in a vertical position next to the sink for him to hold when he stands to brush his teeth. Are there any other places it would be useful do you think?

Any thoughts or experiences you could share would be great!
Thanks
Lucas