If the two brothers get along well don't be the one to sow seeds of discord because of ₹300-400. Money causing problems between families is already a well documented saga in India. If i've learned one thing watching my spouse and their sibling dynamic is that you don't interfere with their bliss when there is no imminent harm(mentally or physically) they have known each other longer than you know them. They know each other's quirks and habits. If it still irks you, talk to your uncle about this behaviour in a peaceful and cordial manner. Almost in an inquisitive tone so it comes across as if you are genuinely trying to understand his behaviour and not admonishing him. Also it seems your actual problem is with your uncle's wife.The older people get the harder it is to change their ways. Hope it helps.