Elderly father was convinced to sign over the deed to his house

I am the POA for my elderly father (in TN) who has some severe memory loss. Basically he has no short term memory, but is able bodied in all other aspects. He lives alone but has a caretaker several days a week.

He has a rental property that he receives a few small income from eachonth.

Today I found out the man who lives in this rental property convinced him to to sign over the deed to the rental house. This happen yesterday and we found out today after EOB.

The tenant knew I was out of the country, took my father into his lawyers office and now has the deed to the house in his name.

Is there any actions I can take to reverse this?

My father's estate lawyers have been notified, but what can I expect to happen, if anything?