It’s appropriate to talk to a college coach if your son sustains an injury. Or if there is a family emergency/situation that calls for an adult conversation. Beyond that you had better read the room. Most coaches don’t want unnecessary contact with parents. There are occasional exceptions. But generally speaking the environment varies by division. With D3 being the most relaxed and D1 being the least. A D3 coach is more likely to have general conversation with a parent than a D1 coach. JuCo coaches are all over the board. Old school coaches are less likely to talk than younger guys. This is a gross generalization but it’s pretty accurate.