The statement about billionaires is true, but also the reasons that people end up living on the streets are extremely complex and I'm not sure this sort of thing helps us actually talk about the real problems.
For instance, a lot of homeless people in the US are foster children who aged out of the care system:
Nationwide, the data show that an estimated 50 percent of the homeless population spent time in foster care.
Money could maybe provide more resources to care for people, but the core issue here is that adults who were foster children lack the support of a family - which no amount of money can fix.
A more useful question to address homelessness would be "why do so many foster children struggle to become self-supporting adults, and what can we do to prevent that?"
I'm not sure that I agree... a family is a lot more than a source of economic support. No amount of less hostile world can substitute for the social, cultural, educational or psychological functions of a family, and becoming a self-supporting adult has a lot to do with mental well-being (in addition to the economic aspects).
Maybe if there were less economic pressure overall there would be more functional families and ultimately fewer children in the foster care system... but that's really just conjecture and I'm not sure how you'd go about trying to support such an argument with research.
I'm also curious how you define "hostile" and "normal humans" in this context.
Money could maybe provide more resources to care for people, but the core issue here is that adults who were foster children lack the support of a family - which no amount of money can fix.
billions in dollars taken from billionaires to help them for a few more years would absolutely help. maybe not all of them, but any that it does help would be well worth it. billionaires don't need more than one yacht.