Ladysuie - I do understand your anger that your son is treating you differently from his MIL, but acting as guarantor is still not a good idea.
As we get older, we have no idea of our health needs, going forward. None of us know what any government will do with pensions/top up benefits, savings etc. We can never promise that we will always be in a position to do anything.
I really think you should think very carefully about giving up secure social housing for any private let.
Once you leave, it’s hard to get back. Social housing is thin on the ground.
Landlords can and do sell up, and you will have no say in it. Rents tend to rise faster, and be higher, than social housing (or, at least here, in a London suburb). My rent, for what I’ve got, would literally be double if I rented privately.
And, I’ve never needed to offer up anything, or find a guarantor.
Your son has made it clear that he can’t/won’t help you.
I do understand that you had happy years there with your late husband, but he’ll always be in your heart, wherever you live.
You said, previously, that some sort of sheltered housing would be a long term preference. You will find it much easier if you are already a social housing tenant to be slotted in.
If you need any adaptions, for physical health needs, social housing providers facilitate this - private landlords won’t.
You can drive - you could always have a few refresher lessons, and buy a little car, which will solve your isolation worries.
Like me, you are alone now - decisions need to be made using hard, cold logic, and thought through.
None of which detracts from your son’s poor behaviour, of course.
I don’t know why the (usually) happy time of a new baby has needed so much angst and drama.🤔
But, he is what he is, and you need to think with your head and not your heart about your own well-being.💐