Ayurvedic tablet to improve Immune systm

My Son got Fabrile Seizure 2 min twice in 3 month gap and admitted 2 times and given medication during that period. My Question - Let me know any Ayurvedic tablets and Chayamprash for improving Immune system. So that No infection and Hence no Fever, so no fabrile seizure. Right now we are giving Baidyanath Jhansi Chayamprash and some times Baidhnath Jhansi Baalrogantak tablet. Is it ok or any other option. As of now, As per doctors we are now giving Frisium 0.5 mg to 1.5 year child during 3 days fever for avoiding or preventing Fabrile Seizure. After giving Frisium 0.5 mg to my Son, Now abke to precaut and avoid Fabrile Seizure after Many Doctor's Recommendations. 2nd question - Is Frisium tablet is safe for brain's Development. Any other Alternate medicine or salt in place of frisium 0.5 mg.