You will need to begin packing at some point. There will come a time when you can broach the subject of moving and just say "H, I'm getting ready to start packing for the pending move, and would would like to know what you wish to keep or donate." It's not a direct question asking him if he's moving with your or not. I suspect he may very well tell you to donate most of the stuff he left behind.
Try to have a good weekend. Do something for yourself.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
