Read your policy. Almost certainly, only you can be subject to an EUO as an insured. This has been litigated in many states, but I don't know about Mass.
If you'd like to discuss, please feel free to call. Jeff Gold Gold, Benes, LLP 1854 Bellmore Ave Bellmore, NY 11710 Telephone -516.512.6333 Email - Jgold@goldbenes.com
I'm sorry to hear about your situation. Unfortunately it is virtually impossible to prove a DUI after the fact. I would retain local counsel to come up with a strategy. It doesn't sound like a strong case if you went the DUI angle but you could get her for something else.
Sign up to receive a 3-part series of useful information and advice about personal injury law.