usually in Joint family - building a house is usual case in Nepal since buying land in city is very expensive. When the time for separation comes, that time, brothers needs to be honest. If only 1 brother spent the money to build the house but other did not, still that brother can make claim. According to law, since it is "Joint property". earned property in joint family is shareable between brothers regardless of who contributed how much!
My own personal case: I Purchased a land and house in Nepal and I am still in joint family. my contribution is 100% and my brother 's contribute is 0%. He was small and student that time.
I have already made my mind that I will have to share it with my brother and I am happy about it. Let's say If I did not want to - he can still claim his part and can win.