Water damaged linoprint

Go to the best reputed framer in your area. Remedies aren't always built on expense. Let him or her talk.
And then go see what the next person says.

I have limited experience re framers in a geographical area, but that can matter.

Many years ago I was interested in printmaking (etching, etc) and there were adviseries about for all that. So far, all my prints remain good, decades later.

In my mind, it starts with the paper, never mind the drawing.
Get the **** the mold away.
That was about the first thing they taught in print class.

yeh, the possibility of "foxing" which is a mold that will creep up an ruin your print starting along the edges, needs to be addressed. As osso says, you need to get someone with experience in this.
Do you have the linoleum block from which she printed it?

Go to a framer and have them replace the mat. Mold spreads eventually and you don't want the image to 'catch it'.