It is possible to let a property to a relative and for them to receive housing benefit.
The local authority have to agree, and are, it seems, more sympathetic with retired people than other benefits recipients.
The gift of the property is an issue, because that isn't allowed - the person making the gift has made themselves deliberately homeless and has deliberately forgone something that they could have used to support themselves.
So means tested benefits will be limited or unavailable - as noted above, google "deprivation of capital"
I don't know any BTL lender who would entertain this arrangement.
Similarly insurance is going to be an issue.
When I post, I am expressing an opinion - feel free to disagree, I have been wrong before.
Please don't act on my suggestions without checking with a grown-up (ideally some kind of expert).