First Seizure

Hello, My son is 16, he had first seizure at school about 3 1/2 weeks ago, he was in cafeteria sitting at table watching his phone and fell to the floor convulsing. He hit his face on floor and had a possible broken nose. They took him to hospital in ambulance. He had an EEG which showed focal spikes in right front temporal area. Neurologist believes he will most likely have another seizure anytime within 6 months and that we should start medication. He already has ADHD and is on medication for that already. So I am hesitant to start another medication. The suggestions were Depakote, Keppra and Lamictal. I researched reviews for these meds and am very worried about side effects: memory loss, depression, raging, suicidal thoughts, hair loss, weight gain, bone thinning, kidney stones, tremors, shakiness, dizziness, double vision, slurred speech. I am worried these meds may give him more problems and in the back of my mind I keep thinking, what if he would never have another seizure and I put him on one of these meds and give him more problems. I just can't believe an extremely health 16 year old boy would start having seizures out of the blue. He is scheduled for an MRI with contrast in about 2 weeks, though the Neurologist doesn't believe we will see any problems with it. I just don't know what to do, I worry every time he leaves the house, will he have another one and hurt himself and I will regret not putting him on meds for it or put him on meds and regret that later if terrible side effects. Any suggestions or input on these medications or anything else would be extremely appreciated!