Does Vestibular Syndrome also have confusion and yelping as if in pain?

I hope someone can help as I’m getting desperate. I have an old black rescue labrador, think he’s about 12 or 13 and he’s been having what we thought was a vestibular attack. The first was about 4 weeks ago and he had the wobbliness, head tilt and salivating quite a bit. He seemed to make a great recovery from that but this past few days he’s taken a dramatic turn for the worse. He seems to have these sort of attacks on waking, which sound as if he’s screaming in pain (not just a cry or a whimper) and are heartbreaking to see and hear. The vet seems to think it could be confusion on waking, and I would love to think that is the case rather than him being in pain but has anyone else seen these symptoms? Noone else I know has had a dog suffer this and I’m desperate to find someone who has gone through this too. He makes no other sound when he is awake apart from sometimes being a bit depressed and laying about and other times he’s up on his feet pottering around.
Oscar is suffering some sort of facial paralysis as he traps his lips in his teeth sometimes- but other times he is ok.
He is eating normally but has grown wise to the fact we are disguising his tablets! He’s on Pardale, but I also asked for some antibiotics just in case it was an inner ear infection, and also vivitonin.
We’ve been back and forth to the vets- the first vet was less than useless and said he is quite happy (just because he still wags his tail!) but I have since found a vet who is so straight talking and kind who says that we should just give him a few days to see if he recovers and if there is no improvement put him to sleep. Obviously that is the last thing we want hence me trying to see if anyone else has had anything similar and their dog recovered. I’ve gone on enough now but any advice would be gratefully received.