Seizures with no problem identified.

I am consulting doctors for my 3.5-month-old male baby and would like an additional opinion. He developed seizures at around 45 days after a brief cough/cold illness. Currently, seizures are mostly controlled with medication, though occasional episodes occur, especially with weight gain, and are managed with dose adjustments. MRI brain and neuroimaging are normal. Blood tests are normal. EEG shows abnormal left parietal-temporal spike and wave discharges, suggestive of focal onset seizures. Genetic testing (WES) did not show a definite pathogenic mutation, but a variant of uncertain significance in the PIGA gene was found. Developmentally, he smiles, has brief eye contact, watches objects like ceiling fans more, and does not yet have good head control. Kindly advise on cause, prognosis, and further management and anything to worry about the PIGA gene (any issues with development). Thank you.