Also, they're not going to say anything over the phone that they aren't willing to say to the lawyer.. so no real point in calling.
In any case, the point isn't to cooperate with the police. The point is to just find out what the heck the FBI actually wants. Finding out what they want doesn't mean actually giving them what it is they want. She could say upfront that she's not answering any questions and just wants to know what they want from her. If they won't tell her under those conditions, well, she's no worse off than she is today.
In general, don't take health or legal advice from HN. There are other places for that, and there is money to spent well.
Presumably her lawyer advised her against doing this. If you'd bothered to retain a lawyer in a situation like this, don't you think you'd defer to his expertise on how to deal with law enforcement?