Help with MS seizures please!

So my dad has had MS for nearly 30 years (he is 60yrs old now) and has managed to live quite comfortably given the diagnosis and comparison to others with the same illness. This we are so thankful for.
But in the last 2 weeks he has had some major developments.
In just 2 weeks he has lost almost all the ability to walk and suffers from multiple seizures a day. The loss of walking ability isn’t the issue but the seizures are unbearable for him. When they occur his limbs all cramp up, his hands are clawed and his jaw clenched shut. With an overwhelming burning sensation like he’s on fire. (He always remains conscious) The only trigger he can find is when he stands up straight so he now tries to remain in a somewhat hunched position to try to avoid bringing them on.
He spent a week in hospital and was put on steroids but the doctors are struggling to address the seizures. We are desperately trying to find any answers to a form of treatment that can help manage these seizures. Anyone who has experienced this we would greatly appreciate if you could reach out and share any information that may help us. Thankyou!