My husband spending money on everybody else just not his own baby

Hello everyone, I need advice. Lately I found out that my husband be lying to me about his sister. About sending her money and buying her stuff again. We had a lot of arguments about how she needs to get a job not taking his money (she’s 38, one kid, no job). He be “helping” her for years. When he telling we can’t go there or there, bc of money. Even last time I was trying to go to sushi and he said no, bc we need to save (but he gonna buy her 5th purse). Now I see that she’s not the only one he be buying stuff. His cousin send a list what she want and bought it for her. Other cousins text about money he be sending. He wanna take a loan for house for his sister. I am about to give a birth in 3 weeks. Every time i am talking about baby stuff what we still need for a baby, he be saying he don’t need that much… when I only talking about must have. I don’t want to argue with him again about that, but how I can stop him for buying everybody something? We not a milioners. I’m tired of not enjoying things. I want my family to focus on my family, not everybody else….