Real Estate that goes into Trust

What is the name of your state (only U.S. law)?
Connecticut
My boyfriend took out a mortgage for his mom who has since passed away.
Before she died she left Life use to her boyfriend, and once he passed the House would go back to the Trust which is in my boyfriend and his brother's name.
She had no other assets and apparently on one ever filed any Probate papers for her. My boyfriend went to Town hall to get the Mother's boy friend off the Deed and put it in the name of the Trust but was told his mother's probate papers needed to be filed first.
My question is, if the house is in a trust, and they file probate papers, will the house be protected against collectors?
What if they want to sell the house?

This is confusing.

What do you mean by "...once he passed the House would go back to the Trust..."?

What is the sequence of events? The house was part of a trust (revocable one would think)? Then was removed from the trust and titled to his mother? How, when, and in what form did her boyfriend's name end up on the deed?

And now your boyfriend wants to put title back into the trust? Why? Whose creditors are you referring to?