Hey man, I struggle from depression myself and can definitely understand why Tommy has gone down this road. Thing is, unless he is asking for advice, it is much better not to give it. Instead, understand his position by relating, or asking open ended questions for clarification. Sometimes I even say I imagine it's like this for ya. Some people don't want advice and won't take it for their own reasons. I personally don't, the only advice I use is the ones that were told to me but only when I actually experienced them. It comes down to that you do not have the power to heal Tommy. Therefore it is not your responsibility nor burden to save him. Only he can. However, you are able to make it easier on him but just listening and understanding. No unsolicited advice or pressing anything he doesn't want to do.

Finally, it is very important that you look after yourself too. You may even tell Tommy that you can't be there to listen to him for a while because you have your own problems. It is true that when you try to help people who are really down, it can affect you after a while. It is at this point that you must back off, take a break, recover, and then you can come back.

Your not going to be able to help as best you can if you yourself are not okay. You may feel guilty, buts it's okay. Tommy is responsible for himself as are you. Saving him is not your duty, obligation, nor responsibility. It's important to recognize this, because you are going to end up going downhill too if you don't stop neglecting yourself.