Is multiple sclerosis the right diagnosis for him?

Hello doctor,

My 66-year-old father who is a retired school teacher was having a cold and cough for 10 days. One month back, he developed slurred speech and blurred vision, double vision, giddiness, imbalance, nasal intonation of voice, hypertension. Blood pressure was fluctuating. As per him, symptoms were more in the morning and improved gradually as the day passed by. There was no headache, vomiting, seizure, loss of control, bowel or bladder incontinence. Computed tomography (CT) of the brain done at first was reported as a left external capsular infarct. An magnetic resonance imaging (MRI) done revealed prominent right cavernous sinus to correlate for significance there is age-related cerebral atrophy with white matter changes. Doctors first doubted MG then MS. Neostigmine test came negative. He was started on an antibiotic, a course of IV methylprednisolone, lipid-lowering agent, PPI and supportive. Blood parameters showed raised total count (TC), renal function test (RFT), uric acid, serum glutamic oxalate transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT). Cerebrospinal fluid (CSF) analysis showed raised protein and total count (TC). With treatment, a bit of improvement was seen but not substantial. Ten years ago, he was diagnosed with retrobulbar neuritis. Doctors are more or less supposing it to be MS and gave a further course of prednisolone of 20 mg and Atorvastatin 20 mg tablets along with those for hypertension, cough and acidity and advised to take care about the blood pressure. There are no definitive answers or assurances. What should we do? Please help.