Let me clarify - what they did is not mooching in my eyes.
Moving across the world is rough and having family there is a great thing and I don't see any issues with it at all. I just think at this specific point after moving months ago is not the time to sit there and say "well I don't like working, so I'm going to use my parents to start a new job" Like if that had started from the beginning of moving (or a month or so in) that it'd be far more understandable. If they are looking to move out and get a car, I don't think this is the time to gamble with starting a new business.
I can understand why he'd wait to start something new. I can understand wanting to really settle in a place. I can understand the need to have a more quiet environment to work (boy do I!!!!) and thinking that after everything is far more settled that it'd be a time to start then.
I don't think it is wise to say "Hey you have your parents, so just rely on them" because for me I'd be working on getting out of there to get my quiet environment to work, not finding something that might cause me to stay longer in a place where working might not be good.
As for my family I could live with most of them. My dad gave us enough space when we were at his house, but I just can't do it long term myself. It's a total pride thing and nothing else. If it were me moving across the country or something like Luis dying I'd definitely rely on my family more. I just would try to get on my own as quick as I can
EDIT: the whole mooching thing was specifically for fly's comment about parents making for a good back up plan. I think that's a poor mentality to have really. Try on your own first and if you absolutely need then go for help, but IMO jumping to a new business without much thought while a partner is unable to bring in income and having a child is not a wise thing to do. If you were fired and relied on your parent that's one thing, but to just quit and not have a real plan and have a family to worry about is another.