Husband wants to give money to loser brother and sister?

Talk to him about how you feel. Let him know that if he wants to give them money, it has to come from his own personal funds, not your joint account. If he still wants to bail them out all of the time, try offering your home and emotional support to them, not your cash. Try and help them both find careers, or something else to keep them busy and give them a sense of independence.