Purchased a 9 his size. Returned for a 10. Got a 9 again. Returned for 10 again got a 10 but they are still short in length. I am keeping them for me. I would suggest 2 sizes up if he has long toes.
Pros
Thermoplastic Rubbers sole
Cons
The slippers can be heavy and cumbersome, adding unnecessary weight to a person's feet