I am sorry about your friend.
The issue is still security. The legal system is designed to make sure that no one can have access to the information on the phone until they prove they are the rightful owner. That is what the subpoena is for.
If I were a Verizon customer, I would like them to be very careful helping people break security until they are absolutely sure that the people asking have the right to the information on my phone. They have the duty of protecting the privacy of their customers.
I think the legal process sounds like the correct way to go. I don't think there is anything else you can do. I would wait for the subpoena.