How to get enrolled into a PhD program without a reference letter from a PI with whom you have worked for 2 years?
If you are going to reveal your past mental health issues as part of the application process then you may as well also say that your past PI reacted unreasonably to your leaving. I don't think you need to "explain that away." Not everyone acts correctly and it sounds like you were treated badly. 

It only becomes an issue, I think, if you don't want to reveal that past, for whatever reason. That is your right, of course. In that case, you should depend on recommendations from others to carry you forward, as well as the publications you developed under this PI. Your written materials need not necessarily mention that he was, in fact a PI. However, if it comes up in an interview, you can mention as much of the past as you need to. His name will likely be present somewhere in your materials and it is possible he will be contacted, so be prepared for a full explanation even if you don't introduce it yourself. 

But if you are asked directly why you left, you can start with "an unresolvable conflict with the PI." Whether that is enough or not depends, but what you decide to say further is up to you. 

But a lot of questions on this site detail various kinds of unreasonable conflict with advisors and PIs. so it isn't a unique problem. Your application materials need to stress that you will be a success.



While your geographic constraint seems to work against you here, it may also be that the opinion of the PI isn't necessarily very positive. So the fact that he is talking about you may not matter as much as you fear. But the only way to find out is to get out there and speak for yourself.