Covid recovery

My Dad has been in hospital due to covid for two weeks. He’s testing negative now and wasn’t really that symptomatic but for some reason it’s made his confusion and mobility really bad. He’s 74 and was previously able to walk up the stairs albeit carefully and walk through the house with a walker. He had carers twice a day to help him dress, wash and make food for him but could manage simple tasks like walking to the toilet and the kitchen. Covid has led to him not even being able to stand up without two people helping him and he’s still quite delusional. This literally hit the second he had covid. Before he could be a bit confused about simple things but nothing like this. Right now he comes out with all sorts of strange things. He’s been tested for Alzheimer’s but that’s not it. I know it has only been two weeks and I thought it could take a few months sometimes to improve though every nurse or consultant I speak to seems to say something else. They started physio but have decided they haven’t seen enough improvement to send him to rehab. I know everyone is different but am looking for stories of people who had something similar. Can’t find any stories out there but he can’t be the only one whose PD symptoms deteriorated like this. I know there’s a chance he won’t return to baseline but wondering if anyone has seen any type of improvement as I know it can take months to recover or see improvement with covid so surely this is the same for PD too or is there just no improvement to be expected?