OP, I've just been through what you're describing, well still going through it really, but I hope you can read this and get some relief from worrying a bit.
We got 6 months notice from our landlord who was going to be selling our private rented house in October last year. I care for my parents and we had been there 25 years, since I was about 10, over the years my husband moved in, we had children and all lived together.
My parents luckily found a one bedroom flat.
We couldn't find anywhere to privately rent before the day we had to move out.
We told the council what was happening beforehand, and they couldn't do anything until the day of "eviction".
So on the day, I had to ring them and say we were homeless, honestly one of the scariest phone calls I've made in my life, I did it with my mum so I could have done support, I was sweating and shaking. We had no idea where we'd be going, couldn't answer the kids when they asked etc.
They put DH, me and our three kids in a Travelodge 40 minutes away. Obviously not ideal, but I was so grateful we had a roof.
So, we were homeless, got our first (and only) food bank voucher that day aswell, because I'd had to bin all my food. Social services didn't get in touch once. My eldest sons autistic with an EHCP aswell. Even though our kids attendance dropped massively, because of the change at first, and then we couldn't afford the petrol money sometimes. I did tell the school this and they couldn't have been more supportive and helpful. We had no fridge/ microwave ect so had to rely on sandwiches and stuff and our family having us for dinner, if we could afford the petrol to get there lol. But, it is what it is and we we're together and housed.
We were there for four months and to be honest I do think we're all still processing it, it was pretty shit, but like I said, I was just grateful to not be "street homeless".
We got a temporary house just a month ago, it's still 45 mins away from where we want to be but we're getting into a routine again, we've got a cooker and our freezer and sofa out of storage.
I can't see why this won't be the same case for you. He's selling the house either way by what you've said. You're not intentionally homeless, you haven't fucked the house up, you have your reports as proof aswell. Either way, you're going to be moving.
It's absolutely horrible, especially when you don't know how social housing or temporary accommodation works. I had no idea at all, but I just had to trust the council would find me somewhere (anywhere!) on the day like they'd said and go with it. I had loads of sleepless nights and tears, but my families coming out the other side of it now and hopefully a private or council house will come up soon by our home town. I never thought we'd be in this situation but we are.
I hope this takes a tiny bit of anxiety about the what will or could happen away for you!