any toiletries are confiscated on arrival, as the prison is unable to confirm contents. prison toiletries will be issued including razors upon arrival, he will get a bed pack that includes a towel
depending on the prison they do have slight differences in what you can take in had have in possession. if tops and trousers are all black they will not be allowed, also hoodies are normally confiscated.
But a rule of thumb;
7 underwear
7 socks
3/4 trousers
2 shorts
4/5 tops
3 footwear
1 x flipflops for showers (never go barefoot in those cubicles)
books
Small radio (some might allow it, but others might claim it could be hiding contraband!!)
If you already know the prison he might go to, give them a call and ask what is allowable as they will give a detailed list. Anything that is taken and is confiscated will be placed in his property box (unless perishable) and will/should be returned upon release.
Take slightly over what he is allowed, as if items get worn out or damaged he should be able to exchange the items that are in his property box (again depending on local rules at the prison) If he does end up being taken into custody and is missing any items, you can either take in or sometime send in the bits he needs normally within the first 28 days and obviously there are rules on what can be sent.
Best of luck