Bottom line is in D1, a team basically HAS to have 8 kids on the roster that are not on a baseball scholarship. Does a coach fill those spots with crappy players that they don't want and have no chance to make the team? I wouldn't think so. If a coach can fill those spots with quality ball players who get a bunch of academic money, I'm sure he's as pleased as punch. I don't necessarily think that just because your son is not getting baseball money, it doesn't mean the coach doesn't like you. Especially if your son is getting a bunch of academic money.
Whether the coach really likes your son is a judgement call you and your son are going to have to make. No one on this site can give you a definite answer one way or another. I would say if the coach promised you a guaranteed spot on the 35 man spring roster, that's a pretty good sign. Unless you think he's flat out lying. Only you can tell that by your interactions with him or looking at past history.
Like I said in the beginning, every D1 team HAS to have 8 non-scholarship players. It doesn't mean they don't like you. They may love you because you are good and you get a bunch of academic money. As others have said, even if your son had baseball money, that is a year to year thing. Nothing is guaranteed.