He’s flaky af but I know he likes me

He’s a grown ass man, 15 years older than me. He’s always been flaky even when we were friends. He’s so hot and cold. But the thing is, I knowwww he has proper deep feelings for me. Everyone and their mums know and when we’re together he lets me know and you know when you can just tell... so why the hot and cold behaviour? I am really starting to fall gor him but I don’t think this will be good for my mental health if he keeps acting like this. I dont know what to even say to him, he’s one cold again! Shall I just call it a day with him?

Also, he hasn’t been in a relationship in over 5 years, could this be it? Do I need to be patient?