PTs are the most common type of brain tumours in rats, although there can be others. If his from paws are involuntarily stretched forward and he's making fists, that's an indication of PT.
I didn't think PT when I made my original comment, although I have had PT rats with seizures (usually towards the end) the nose bleed isn't a common symptom.
The head shaking also makes me think he could have an inner ear infection or a growth in/near his brain.
With PT, the sooner treatment is started, the more likely it is to help. The more the tumour grows, the more (brain) damage it does, and it's often not reversible. I don't see why that would be different for another type of tumour.