I guess I am weird but if I had a ton of money and my brother didn't then I'd be pushing my parents to give most/all of it to my brother. If they didn't do so I'd give my inheritance to my brother.
I think it would depend on the circumstances. For instance, my Mom is a lot better off financially than my uncle (her brother). She probably has about 4x more saved up than he does. My uncle is bad with money; he freely admits it. Grandmom's will is set up to go 40% to my uncle, 40% to my Mom, and 20% to me, the only grandkid.
My Mom doesn't need the money. And I don't, either, although what I get could potentially put me a year or two closer to retirement. My uncle, though, while he would benefit greatly from the money, wouldn't know how to manage it. He would end up like one of those rags to riches to rags lottery winners you hear about.
So, splitting it up this way, at the worst, he would potentially only blow 40% of grandmom's estate. Whatever Mom got would most likely get put into something low risk/low return. Whatever I got would most likely be invested, more risk, but more return. So, 60% of the estate would remain intact and even grow, hopefully. And my Mom and I would be able to use that money to help out my uncle, if he got in over his head.
Of course, a plan like this only works if the well-off relatives are willing to help out the poorer one...not all families are willing to do that.
In my family's case, for example, that 40/20/40 split also includes Grandmom's house. My Mom keeps worrying that my uncle won't be able to afford the upkeep, utilities, etc once Grandmom is gone. But I keep reminding her that, on top of the house, there's whatever money that he would get from Grandmom's estate. Plus, his own 401k and IRA. And I also reminded her that she and I could help him out, if need be, to pick up a utility bill, help with the property taxes, etc.
We've both decided that neither one of us wants him actually living WITH us. Right now, having him at Grandmom's house across the street is close enough. At one time, I would have considered getting a house with an in-law suite...either in the basement, attached on the side, or separate. But I've come to the realization that having my family that close would drive me crazy, so when the time comes, I'm thinking about just helping him get a small, cheap condo or townhouse somewhere close by.