PIN; Need to enter IRS assigned PIN

My wife and I were separated and she did our taxes in CO and I lived in WY and still do. She passed away before the divorce was final and took all the info including the Pin from the IRS literally to her grave. I have no way of retrieving it and at all it was done because her brother stole my identity. I don't remember her email etc. to access this info due to her erasing it all before passing. The IRS has been no help in getting this info. This will be 2 years now that I can't do anything including helping my son who is autistic with no speaking abilities who gets compensation for survival benefits. I am remarried now but, this has made no difference in my situation. How do I get the pin since I can't prove who I am? In the IRS's eyes, I'm still a stranger with no aves of recourse. There must be a way to get this resolved otherwise I'm afraid of legal repercussions very soon. Do I need to hire a lawyer or can I get this fixed on my own?! Thank You for your time and understanding