How to stop caring?

So my sister in law (my husbands sister) had a baby two years ago and her and her husband don’t work and try to live off the government to raise their kid. their kid suffers, barely has food on the table, lives in a small bedroom with them, in complete and utter disgust. Now they’re having another baby they just announced. The whole family is so excited and i’m literally so mad because they’re like condoning what they’re doing and it’s IRRITATING ME. They make excuses to why they can’t work and say they don’t want to and that the government will do it for them. How do I block them out of my life and stop letting it bother me and stop worrying bout their babies 😢 like why is her family not telling her it’s soooo wrong what they’re doing! I tell my husband and he says “who cares it’s not us don’t worry bout them”