Depression can often isolate someone, some people like myself wont show "weakness" just like you mentioned. Mainly because of our upbringings, it sounds like he doesn't get alot of support from family if he breaks down like that. He is probably very uncertain on what to do, maybe he wants you to reach out to him and ask him out. I don't see why that would be weird, the world is changing and I see nothing wrong with a woman asking a man out.
I don't know whether he has bipolar, this is merely an hypothesis at the moment as there is no confirmed diagnosis (so I won't go into that).
I think at this stage, don't tell him he has a problem or may need additional help, let him seek it out for himself as he may take offense to it. The alcohol will play a big role in him expressing emotion, he may be embarassed and possibly turned off after telling you about
his depression. I don't think he should be embarassed, because statistically a massive % of the world has depression or some underlying condition.
My personal suggestion is, invite him out and don't talk about
his depression, because you don't want him in his shell, you want to bring him out of his shell. If you can show him that everything is ok, then he may bring it back up or maybe not, even so atleast you're not left in the dark.
Good luck and hope you make a decision that will suit you both.
edit PS: Also if he likes to drink, maybe make sure where ever you go there is alcohol available (I mean, don't take him out of his comfort zone). He may be using alcohol as a self medication, but I don't know. If he then blows you off for asking him out, then I think you know that he has probably lost the plot. Even a nice quiet environment to a restaurant or a pub meal? But make sure you don't speak of what he told you, if it come up on conversation then probably best not to feel too sorry for him, as you don't want him to feel "weak".
If you can also, actually call him and ask him, don't text because I often miss texts while at work or ill forget to reply to an old text. Doesn't always mean that someone is ignoring, just means that some people have poor memories lol.
Post Edited (Crackles23) : 8/11/2011 3:15:15 PM (GMT-6)