I mean, sure, it could've been a crazy ex or a former business partner or whatever. But how many crazy ex's can one guy have? And he's pissed off god knows how many people by saying things? Strictly by the numbers this was almost certainly someone who hated him for what he said.
Statistically most people don't go out like Ozzy (i.e. spend a good chunk of your life doing something likely to be the death of you only to get dead by something completely unrelated)
Please do Obama now. All U.S. Presidents from both parties have been doing these sorts of interventions for decades.