
I say focus more on the 'job in the future' thing. If he's offering a job in the future, and it has definite time frames, you can be assured enough that you're doing a good job and he's not BSing you.
Most of the jobs I've worked, if I'm doing great I don't hear a thing, and if I'm doing badly they're down my throat. So no news is typically good news for me. But, then again, everyone's boss is different. He could really just be one of those testy, anti-social bosses that doesn't realize that a little bit of free words and validation go a long, long way to making employees happy.. or he could be BSing you, feeding off of your volunteer hours, and getting as much as he can while he can. Impossible to tell from where I'm standing.
I'd wait a while, and then ask about the job opportunity. If that keeps seeming shady, I'd bet the rest of it is too.