Its easy for me to give advice now that we're done with recruiting. I can tell you not to worry because it will all work out in the end. But the fact that you're asking here, tells me that you are worrying, just like we did!
We had the same situation, but our HS coach wasn't young. Just inexperienced with recruiting and pessimistic by nature. Still can't believe that my son got the attention he did and signed D1. Now the pro scouts are calling for schedules this spring and the man still doesn't believe that all this is happening.
Good players get seen by scouts or college coaches and are judged by their ability. I really don't think the HS coach has much to do with it. Ours filled out questionnaires at his leisure and continued to doubt our son till the NLI signing day. I have concluded two things:
1. College coaches have seen all kinds of HS coaches. The above advice to list multiply coaches gives the recruiter backup contacts.
2. Sometimes it seemed like the HS coach was just a reference. Kind of a last chance for the college coach to hear something dreadful about a kid like substance abuse, poor academics or bad attitude. When it came to baseball, the college coaches always made their own decisions.
Maybe some day our son's HS coach will see my son on the college field (or can we dream he might be on a pro field) and admit that this all was deserved. But knowing his personality, I'm not holding my breath! We have a younger son who will attend the same school, so I'm being very careful not to burn any bridges. But someday....Nah, he really isn't worth it!