It was hard enough work getting him out to dinner with his kids. Multiply the difficulty level with travel & flying even with the help of the airline. I wouldn't even consider it if it were me. Add to that how they treat you. I would tell him if he wants to go that bad he can arrange it for himself & just travel alone.

I would feel seriously taken advantage of & disregarded by his family. I would distance as much as possible right now while these feelings are so strong & see where they go in the future.