I'm sure she has already thought of this but if she states in her postings that she is looking for a home with no other cats or a family that already has FELV cats it will save alot of time rather than telling them after the fact and having everybody back out.
It would be ideal if she could find a family that has an FELV cat that is lonely and needs a companion. This way they could have each other and not worry about passing the disease onto each other.
Prayers that this family is out there.