1) One of his friends who plays soccer came to our restaurant last night.
2) One of his friends who play soccer came to our restaurant last night.
I think in '2' he has a number of friends who play soccer and one of them came to our restaurant last night.
In '1' we don't know if he has only one friend who plays soccer or more, but the former is probably more likely.
Is that correct?
Gratefully,
Navi