Mine is the same. BC version 1, he was 13 so somewhat excused. BC version 2, he was 24 and no help at all. I was also a single mum, maybe I was too resilient? Too tough? Too busy? Who knows. The thing that shits me is he (also a FIFO) called in to see my mother and begged off staying with her because he needed to come home and help me. What?
I rang him the other day, 'Please come and help me get some wood in for winter.' Nup. Going bike riding.
Look, he doesn't ask for much (probably justjas well as I don't have anything left) and he isn't rude or abusive. He's just 24 and not available. So it goes.