Thank you all sooo much for your replies! It's so nice to be able to talk about this here. I'm very touched by how much you all obviously care.
Nohope, thank you so much and I am so sorry for your loss.
David, I think you really hit the nail on the head about what he was/is feeling concerning his GF. As far as the God part goes, after talking with him a lot, I think he is mainly questioning how God could allow things like this to happen in the world more than he is actually questioning if He actually exists. In fact, he went to church earlier with a friend. We talked very candidly and I hope we have gotten accross to him that God is cruel and that he will not hold this against him. We have talked to him extensively about God's LOVE...I believe that reaches much farther than preaching God's wrath and scaring the beejeebies out of people LOL (just added that so that you won't all get the idea that we are the types of parents telling him God is going to punish him for things, etc)

I have wondered if perhaps the biggest problem was that he wanted to do something so bad to his GFs dad that it was either him or himself at that particular time...
As for the lexapro, I don't believe it had anything to do with the suicidal thoughts. He hasn't taken it in some time....he never really took it regular with the exception of the 1st two weeks, but that was several months ago. I should clarify, he never actually took the higher prescribed dosage because at that time, the pdoc told him to take it 10days in a roll, then raise the dosage...he never took it 10days in a roll after that. He hasn't taken it at all in about 3 weeks or so.

His pdocs attitude really bothers me. He just didn't act like it was serious at all...he said he didn't think he would do it again. He rolled his eyes once when I was talking, like I was overreacting

On a good note, my son went to school today and things went very good for him He was very scared to go back because we live in a very small town and some of his friends had already called him saying they knew. Evidentally our hospital staff has problems keeping their mouths shut. But he had a good day, the kids were nice, and then like I mentioned earlier, he went to church with a friend tonight. I'm optimistic since he is interacting with friends now. I don't feel that he's "out of the woods" yet of course, but I'm hoping and praying that he is beginning the road to recovery. He sees his tdoc tomorrow and I'm going to ask him for a referral to a different pdoc.
Again, thank you all for all of your concerns and help!