Feeling guilty and incredibly sad about the situation my dad is in

You poor thing.

I’d suggest what others have, I’d investigate homes in France.

You have done the most amazing job taking care of your father ! Sounds as though your father has dementia, does he have a diognosis? Please remember that his behaviour would be exactly the same wherever he was and this is in no way your fault !! Admiral Nurses in the UK are dementia specialists please ring / email them for support - he does not need a diognosis to enable you to do this. My heart goes out to you and and I recognize your pain. I send you strength and ((( hugs ))). If your father does have dementia he will need a specialist nursing home , continue to pester the social worker. Above all look after yourself! What is happening is beyond your control so do not beat yourself up about this.
Sadly if dementia has really taken hold there is little you can do to keep the ' beast at bay ' other than ensure he is in the best care home possible.
I know this sounds harsh and I know how much you love your father but please remember you have done nothing to cause this situation.💐💐

A few years ago I was in a similar situation.My Mum's health
deteriorated and social services put her in a not very good care
home, the level of English spoken by the staff was not great.
I decided to bring her to my home town in France as dementia
had set in as well.
She didn't speak French but the staff tried hard with what little
they had and another lady spoke English . I visited every day
even for 1/2 hour sometimes and she lived another 3 years there. I'm sure my daily contact and her grandchildren's visits kept her going, she didn't feel abandoned. It was not
easy for many reasons but I have never regretted that time
and the French home was well staffed and - at the time - cheaper .

How hard for you - but don't feel guilty - you took him in and gave him a home in France for many years.

What has happened now is simply inevitable with the passage of time, but complicated by the different countries.

I think the idea of buying in some extra carer time to take him out and about is a good one.

There will be no ideal solution to this scenario, so please do not feel you can find one. It is going to be all about compromise. I hope you can find some way forward.

The ball.is firmly in the social worker's court. All you can do is pressure them.to find somewhere suitable. I hope it all works out soon.

Sadly, it sounds as though a new care home in England is going to be the long-term solution, if the social worker can find him somewhere fairly soon.
I just wonder, could you see if you can pay for a carer to take him out privately a couple of afternoons a week? I've no idea if that's possible but it does sound as though he misses being able to get out & about, & that might improve his quality of life (if it works).
I'm sure his talk of abandonment is the illness talking, not what he would think if he was his old self. It's still all heartbreaking for you though, I really hope the situation improves.