Most Helpful Girl
It could very well be, that he May have told her about 'His family holiday' and it ended up putting a sour ball in her mouth And... The relationship went south.
Anything could have happened that lead to the 'Break up with his girlfriend,' but in this sticky situation, don't wear your heart so quick on your sleeve. You never know what he has Up his sleeve with her and him going back tomorrow and Him... Leaving you sitting alone with no dessert.
Go slow with this family flow. I find it nice as spice that he asked you to join this joyous occasion. But you don't know just yet his motive in mind so go so better not to put the sweet before the main course just until you see that there may be More in Store.
Good luck. xx0