Will never got much heat here, and I regret that initial idea that seniors are ok to attack. Most piling on gets deleted these days, especially if it is reported.
The basic gist of what his friends have said, along with his own words, is that nothing like PSR drove him anywhere. While it is hard to understand what he did, it was about his own hard-wiring and how he perceived his world. His professional life was fine--plenty of connections, plenty of friends, not at all isolated, appreciated very much by his new colleagues. So, folks will try to figure it out because that is the natural reaction, but we will never know his inner life and how he felt about stuff.