Hi @Sam40. I am very sorry that your friend is in this difficult situation.
(And thank you @Cade_One for tagging me. I have not been very active on here lately.)
Before I would respond, I would like to mention that there are a lot of things I don’t know about the situation that could be relevant.
I have had to keep re-writing my answer because a lot is confusing me about this situation:
-Why is she being prepared for Confirmation if she cannot receive Holy Communion? (That seems highly unusual.)
-Why is her advocate (which I assume is another word for sponsor) speaking to her about this rather than the parish priest (or another clergyman or a parish staff member)?
-Has there been any conversation with the parish priest about this?
So please pardon me if this seems like a rather sprawling answer.
It is true that someone in an irregular marital situation (or anyone who is publicly living in a seriously sinful situation) ought not to receive the sacraments. This is in accord with the ancient tradition of the Church. In my own diocese we have a policy of not admitting candidates into OCIA until any marital irregularities are resolved.
Basically, the options of leaving an irregular marital situation are: a) separation; or b) seeking a remedy through the marriage tribunal (or whatever it may be called in your locale).
[Also, I assume that to “confront” the man would mean to reach out and ask for his contact info, since - as far as I know - decree of nullity cases do not require direct confrontation between the two parties (however, they both usually have the right to know that the process is taking place).]
In my diocese, the marriage tribunal is open to processing cases for a decree of nullity without informing the other party if there is a serious reason to do so. It’s possible that the local marriage tribunal might be willing to considering doing likewise.
If her advocate is indeed her sponsor (as I have assumed), it seems unlikely that the advocate would be the best person with whom your friend should discuss the decree of nullity process. The advocate sounds like a faithful Catholic and is right that your friend cannot be in an irregular marital situation. However, the advocate probably does not have as much information about how the marriage tribunal works as others do.
This should be discussed with the parish priest. Or, if the parish priest has been tried but found wanting, then your friend can contact the local marriage tribunal directly.
With regard to the fact that you feel that the situation seems wrong: I agree that this is not a good situation. The advocate is right that your friend ought not to receive Holy Communion at the present time. But I think this should have been addressed before your friend was allowed into the program.
Please be assured of my prayers for all involved.