I'm pretty sure there's more to the back story that led up to this, and I've encouraged him to write more about this at some point when he's more stable. If I were to guess, based on the few points he's made in writing, there's some family rift going on, and I might also presume that he may have been paying for things for his mother that might have otherwise gone in to savings.
He's been through a divorce, which can certainly have a financial toll on anyone, and I think it was a bit later in life, which may be harder to recover from.
A late divorce, some health problems, trying to support a family member - all of that may quickly deplete someone's funds.
As to the homeless part, I think there's a certain pride involved, and asking for help may be embarrassing, especially to have to involve friends. It may be that many of his local friends would be tied to his mother/family, and may not be as supportive as one might hope.
I sent money to paypal, but it's frozen, and I'm wondering if I can reverse it and senf via GFM and he'll get access faster. Hrmmm....