Although some of these hypotheses are vaguely plausible I think it is outrageous to lay all the suspicion on a potential victim. I'm not saying we should be naive and take everything for granted in this story but the least we can do is assume he's telling the truth before advocating the devil - specially in regards of a mothers death.

Also :

+ if it was holidays or a child he wouldn't have left in a rush : those departure should arguably be prepared in advance

+ "Technological details" are very vague and sounds like something he overheard but didn't understand or know how to use.

+ the throwaway account means nothing and could very well plead in his favour : he's not sure he wants to spend time attacking his company so he stays anonymous before taking a rushed decision.

+ not checking his email is consistent with not having the dongle !