Question about class and families

I stumbled across this on Youtube, and I'm binge watching it. Great series! But something I keep wondering, I'm hoping maybe someone who is English can help me with. I don't get why families seem to help one another so little. I get everyone except the uncle isn't wealthy, but the poverty of the one son (with the wife and two kids) is appalling; why didn't that wife and kids move into the parents' house? Why was giving him a job in the works such a big deal?