I'll leave it to the real experts to give you specific advice about the watch.
When you say heirloom, is it a personal heirloom? Did it belong to your dad or your grandpa? Or is it just a nice old timepiece?
If it's the former, it's probably worth getting it repaired even if you might be able to buy a decent new watch for the same money.
But if it's not, there are watchmakers--including some on this board--for whom this watch would have some value. So don't chuck it out or sell it to someone for $10.
Posting some pics here would go a long way to helping determine what you've got, how much it's worth, and what's the best way to go about fixing it.
In any case, you're starting out at the right place.
best
Allen