I've done this in a couple of ways. Growing up, my sister and her kid lived at home with my parents and I. So technically three generations. And also, I've done this with my husband's family where I lived with him, his dad, his aunt, and two cousins.

My experience is that as a white American person living with a sibling and their kids isn't really that big of a deal, but it really depends on family dynamics. My parents weren't really happy to have my sister there and she had a terrible relationship with them. I think there's a lot of cultural stigma to it, as you note. The idea that people are losers or failures, etc. By contrast, my husband is Chinese and this is very normal in immigrant communities in my experience. People come and go from living with each other all the time. The aunt and her daughter who lived with us moved in with us when they immigrated, and then lived with my husband's mom, and they (mom and daughter) have ALWAYS lived together since getting here. And another aunt moved in to help with the kids. The main difference I see is that it is viewed entirely differently. It's seen as mutually beneficial. You live with me for $500 a month. I make money. You get a cheap place to live. In our case we lived in a home owned by my MIL, she charged us like $500 a month for a 2000+ sq ft house. We maintained the house for her. The people who lived with us paid a few hundred dollars a piece. So we actually made more than we paid to live there. If you ever wonder how immigrant families get ahead - this is it. A culture of helping each other get ahead. And as opposed to being shameful to live with people, it's expected. It's actually really frowned on if you DON'T take people in a lot of times. Or even sometimes if you don't take advantage of saving money by living with other people. My MIL was so frustrated we wouldn't go live with my SIL why we wait for our new place. But I'm honestly over living with other people. I've done enough of it.