A young close family member (let's call them "Alison") has recently broken up with their husband of only 3-4 years.
In order to find friends (or something similar, it's unsure), Alison has joined an online friendship group (I don't know what the actual group name is).
Very quickly, Alison made contact with a young married couple who live about 90 minutes drive away.
For the past 2-3 months, they have been regularly staying at Alison's house, every other weekend, almost since they all first made contact, for 3-4 days a week whenever they do visit.
This couple seem genuine, the female has a physical disability and has been granted a vehicle as a result. Neither her nor the husband is also not in full time employment. It's not clear if there is any sexual link between all 3 of them.
Alison appears to have grown slightly distant from her family, to the point where previous plans made have been abandoned due to the visiting couple.
And lately, the worst part is that Alison has given the couple a key to her (council rented) flat, and regularly leaves them in the flat whilst she goes to work.
I like to give everybody the benefit of the doubt, but something about this just does not seem right. Alison was left a large sum of money by her father, and I'm concerned that the couple may know this from online conversations, although that is just conjecture.
Is this a regular kind of scam? What kind of legal issues is Alison exposing herself, to by giving this couple a key to her property? This is in England.