@hawkeye10,
If Williams was that hard up for money, he wouldn't have set up the trust funds for his three children so they could receive them while he was still alive. His eldest son has already likely collected his entire trust. His daughter has probably collected two-thirds of hers.
I don't understand why you are so determined to view this man as some kind of washed-up failure at the end. He wasn't, not by a longshot. He remained working, and in demand, and very highly regarded by a great many in the entertainment industry, as well as countless fans. He had future projects already lined up.
He struggled with mental health issues throughout his life--particularly anxiety, which he said was at the root of his problems with addiction to alcohol. And, at least since his open heart surgery in 2009, he suffered from increasing bouts of depression. Advancing age, and concerns about a very uncertain future, due to an extremely debilitating and progressive neurological disease, that could have robbed him of his basic independence, may well have been enough to plunge him into a depression and state of anxiety that was intolerable for him, that simply overwhelmed his coping mechanisms, particularly given his predisposition for these problems.
I don't think you really understand that the torment was inside of him--he had battled it for years. Depression itself can be crushing, it can distort everything out of all proportion.