The idea, or even possibility, of a T loving a client? It's feasible.

However, as to the therapeutic value of saying it to the client? I don't believe this is necessarily the 'right' thing to do. Might create more harm as love(*) is a loaded concept and easily subject to misunderstandings or mind***ks.

(*) Even though there are different kinds of love but it is oh so easy for clients to affix their own meaning... or longing onto that term, in the therapeutic relationship. I don't believe it was wise of her to say it to you.