You can be as friendly to him as you want but have no expectations. That's where most of us backslide, H acts friendly, we read into that what we want it to mean then when it's not reciprocated we're back on the rollercoaster. Sometimes being neutral is the best thing. He knows you're there and when he can he will reach out.
Passive men are sometimes friendly because they can't say what they really want. They don't want to make the other person mad, they don't want drama so the go along with their charade until it's too much for them and they back off, stop communicating, retreat. It's their form of control. I've fallen into that trap many times.
Only you know how much of that you can take. Have no expectations.
Have you read much on detachment? There's a great list if you google Livestrong detachment that was helpful for me.
I know this is all so difficult. Usually the best thing to do, and this goes with detachment, is let him figure out what he wants to do and remember that it won't happen on your timeline.
I like your post above about your 40 things. Go for it, this is the perfect time to start.
Me 57/H 58 M36 S 2.5yrs R 12/13
Let me give up the need to know why things happen as they do. I will never know and constant wondering is constant suffering. Caroline Myss