You need to see an attorney. In Florida their are homestead rights, etc. that protect people from this type of situation.
If someone is unduly influencing an elderly person to their benefit then there may be a legal issue there. I would suggest contacting an elder law attorney to discuss the entire situation.
Yes, it is a crime and you should report it to the authorities.
THESE COMMENTS ARE NOT LEGAL ADVICE. They are provided for informational purposes only. Actual legal advice can only be provided after consultation by an attorney licensed in your jurisdiction. Answering this question does not create an attorney-client relationship or otherwise require further consultation.
If I understand your question the husband is now dead and the homestead has been sold. If they were legally married at the time of death and there was no pre nup or post nup, she has at least a life estate in the home and it can not be sold without her permission and receiving a part of the proceeds. If it has been sold go to an attorney and seek help immediately before the proceeds are gone. Also the Buyer needs to be put on notice that he has a voidable deed.
You may also need a guardian for the wife.