I guess it depends.
Am I willing to give up something to make someone else very happy? Yes.
DH is willing to find a new job in an area he doesn't know just to make me happy. We'll be moving hundreds of miles - for me. Would we do it if DS needed it, for example he needed to attend a special school in another part of the country? Yup, we'd both do it.
If he loved football then go play, enjoy! Tennis, enjoy! Piano, enjoy! Maths, enjoy! Do what you love! My mother shuttled me around various stages so I could be in my various drama productions. I would have loved it if she'd have stayed to see them! I know she saw most of the different plays once, but you know what children are like, they want it all. I know she didn't see some reviews we did at all, but still supported me with the driving.
I am not going to push DS into a career (even if DH and I would prefer a non-sporting career, that's DS's choice and we didn't pick sporting careers for ourselves so that's us sorted). If he needs help in his chosen field, even if he doesn't end up doing it for a job but just enjoys it, I'll help. 4am starts, fine. Pack the coffee. Moving somewhere else? So long as DH can get a good job nearby we can move.
So long as it doesn't impact negatively on our other (hypothetical and may never exist anyway) children then absolutely fine.
If I had another child who needed me there at 4am, who was left alone so I could help another child pursue a dream, that's not on. Sometimes you have to say - I can't split myself in two. You have equal needs. You live near enough to get out of bed at 3.30 and cycle there; I'll get up and make breakfast and coffee but I have to stay at home. We'll be there for the big things always, but you put some effort in. Not always but at least half the time.
We, as parents, don't have children to dismiss their dreams! We have children because we love them and want to do what's best for them, even if that means sacrificing something we want.
And Holly - I currently live nearish to London. If we don't move your BiL can have some friendly faces nearby - and if we do, England's not that big, if he needs a big home cooked pasta I'm sure we can arrange it for him. People need support!

