I sympathize with your plight. My son's coach also does not have a regular pitching rotation. Tells players the night before who will be pitching. Similar to you. I can only imagine your frustration. I fear we may be facing this problem too as I suspect my son's high school coach does not fully support our son's interest in playing college ball. And son is a serious recruit with multiple letters from good schools..
An example:
Our son has had serious interest from a D1 school in our city. Last week, the school baseball team had a seminar on Mental Game. This particular D1 coach was invited. My son approached his high school coach and asked him to come up with him to talk to the D1 coach. High school coach ignored him but grabbed the short stop and brought him right up to the D1 coach! To back track, we have had (what I thought) was a good rapport with the high school coach. The coach says very little to son--not much negative, not much positive. To be fair, son is not the most outgoing guy but he's never been a problem, stays in excellent shape, no injuries and works hard at practice. Elsewhere on this website, this issue of indifferent coaches has been addressed. But I would never think a coach would actually thwart the efforts of kid who is being scouted.