My cusion got mad because his sim caught the kitchen on fire and killed his family honestly. So he deleted the whole NeighborHood!!!!! I had a family in it I had play for a long time !.. Can I get it back with out uninstalling and reinstalling the whole game?
I hope so!!!

If he deleted it from within the game, no, it's gone.
If he deleted it from Windows, it may still be in your Recycle Bin, and you may be able to restore it.

Reinstalling will not get you back your lost family, only the default neighborhoods - but you don't need to reinstall to do that, just this: http://www.modthesims2.com/article.php?p=1105946