How does my friend help his mother?

Invite “a friend” of yours (psychiatrist, psychiatric social worker, psychologist WITH CREDENTIALS AND/OR TRAINING IN GERIATRIC ASSESSMENT) to join you for a visit with her for tea, or to chat about one of your or her hobbies, and prep the specialist beforehand about her recent behavior. Request an assessment of cognitive function.

Once you have “specialist’s” report in hand you will have a clearer sense of what you can or can’t do FOR HER SAFETY. Hopefully you can find someone with the appropriate expertise.

Tell family members not to give her any money. Sorry, but for an 80 yr old to believe the man is in love with her and asking for money and is not a red flag for her, there is some cognitive decline. In my opinion a Social worker is not able to determine that someone has Dementia or not.

If possible get financial POA now and have it immediate. Then DH can have some controll over the money.

Unfortunately, this is a periodic and unsettling topic.  There are a lot of posts on this subject:

https://www.agingcare.com/search?term=scamming+elders

https://www.agingcare.com/search?term=scams%2C+how+to+prevent

You can use the icon to the left of your avatar and search on other parameters.

Good luck; this is a frustrating situation and one that's tough to resolve.