I am not fully sure of what you are looking for but this sounds identical to what happened to my Dad. There are some differences and I am going to be vague as they are really outing.
however, he ended up with significant bleeding on the brain and skull fractures. He didn’t live in the UK and waited for appropriate medical care. Like your Dad they didn’t operate as the operation would have made things worse. The thing I found was that it was a difficult balance in terms of you do this you get x result you do that you get y result and realistically few results were good. My dad was in a country where they prioritise saving the individuals life regardless of the quality of life afterwards and that’s what happened.
long story short when my dad finally recovered he had significant difficulties. He had no short term memory so no clue where he was, he couldn’t speak properly so there was no opportunity for a conversation, he couldn’t walk and so on. He did have physio and ot but due to the brain injury he fatigued easily and so it wasn’t safe for him to do much beyond mobilising into a wheelchair. As much as I wish my Dad had survived initially. Ultimately his condition was awful and he was pretty much bed bound, staring into space and I wouldn’t wish it on my worst enemy. He died several months later from something completely unrelated but likely caused by stress.
if this had been in the UK my Dad would have died much earlier and I would have been devestated and screaming into the void. But with hindsight and going on the journey we went on knowing what I know now and how tough, gruelling and frankly horrific the journey for my Dad was I wish he hadn’t been kept alive and that is a regret I will carry with me forever.
It is the most horrific experience when a loved one has an accident like this so so so meaningless and it changes you. I’m not a dr but it sounds like your Dad got the right care it’s just the worst most impossible of situations. Sending love to you and your family and most importantly your Dad as you take the next steps forward.