What can I do when an elderly senior is being taken financial advantage of by a non-family member?

I know a person who has befriended a senior and is taking total financial advantage of him. This person is a realtor and has sold his house and then became this man's Power of Attorney. This man then became very ill with double pneumonia, and had to be hospitalized. While in the hospital, she bought a 32' motor home and a brand new pick up truck with his money. When he recovered, she put him in assisted living, and he was doing very well there. After realizing that this place was too costly, she then moved him into her place where she will not be there to have the care he requires. I am very concerned for this poor man's future and well being. Not sure what to do?