Upside, He's not trying to do anything. He does miss you in his own way. He didn't completely read your response to him. He just skimmed over it and picked up on the fact that you miss him. It's normal behavior for a depressed soul to do this. They hear and read what they want to and leave the rest outside the universe.
If you allow every off the cuff comment he makes drive you nuts, then I guarantee it will. He's just as nutty as a fruit cake. Many of them are like that for a very long time. Others stay that way forever. Let's hope and pray that your h finds himself and can heal...better late than never.
Comments such as his latest one are for the book of crazy comments. Let it go....
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.