She should contact the attorney who drafted the trusts. That attorney should still have a copy of the trust that he or she drafted for the deceased friend. (They did use an attorney and not Quicken Willmaker, right? I doubt the company that owns Quicken will be much help in this situation.)
Your friend doesn't need to go through a dealer to do this transfer, by the way, as long as they both live(d) in the same state. The trust should specify who the successor trustee is for the deceased's trust. That person will retain control of the suppressors and SBR until the ATF Form 5 is returned.
I've never done a Form 5, but I would imagine that the successor trustee would need a copy of the trust, and if your friend wants to put the NFA items into her trust, she'll need to have a copy of her trust handy to send to the ATF with the Form 5 (just as she would when she bought things on a Form 4 with her own trust).
Your friend is seriously best advised to contact the attorney who drafted the trusts, and use that attorney or another attorney to assist her in completing these transfers lawfully.
Aaron
(who is a lawyer, but isn't your lawyer or your friend's lawyer and isn't providing legal advice)