Family member had their first tonic clonic seizure after 10 years

Hi all, looking for some advice. My father today had his first tonic clonic seizure today after only having partial seizures for the last 10 years. He is medicated for his partial seizure but does not take it and without medication they normally only happen every 2 months or so and symptoms are normally rapid blinking or noises with mouth. This was a very scary event for the family as it happened while he was in the bath and at first thought it was either heart attack or drowning and was planning to administer medical aid but thankfully the paramedics in the ambulance that we sent for confirmed it was a tonic clonic seizure, they took him to hospital, give him same medications that he should have been taking (is now taking again) and also IV potassium as this was very low. Just looking for advice about going forward, could this be a once off or something we may have to consider from now on. Thankfully he is ok now just very tired and lethargic. All help is appreciated :)