KE,
I'm adding your encouraging words to my list. Another phrase I just thought of: "Good work on that" (if that statement is in any sense true).
You are further along the path I am walking--where "further along" does not mean something positive. My son does still have a roof over his head for now.
I am happy for you that your son calls and wants to share his plans with you. I can imagine that after every conversation, you want to think, "If he dies and this is the last time I ever talk to him, I will know my last words to him were of love and support"--no matter what his words to you were. This is the thought I always have.
I appreciate so much that I can express fears like that here and know that others understand.