New to the forum - son with high functioning LGS

My six year old son had his first seizure at 4. After trying tegretol (caused more seizures), clobazam, valproic acid and lamotrigine with no long term results (no more than a few months seizure free) and seizure activity increasing he was admitted to an epilepsy monitoring unit. When he was admitted he was having 10-30+ very short drop seizures everyday. After 18 hours of EEG data he was diagnosed with Lennox Gastaut. It was difficult to diagnose because he has met all developmental milestones but the seizures keep changing and meds aren't as effective. He was given a two month pulse of prednisone which worked wonders - after only 4 days on the steroid the seizures stopped. He was then seizure free for almost 6 months. He'd been taking divalproex in tablet form but there was a drug shortage here in Canada so for 10 days he had to take a capsule form of the drug. We also had to evacuate our city due to a major forest fire that left a portion of the city completely gone. Doctors aren't sure whether it was the drug change or the trauma of the fire that caused the relapse. At the time of relapse he was put back on prednisone for another 2 month pulse. Again he was seizure free immediately. We were told patients sometimes require the second course of steroids to send their LGS into "remission" but a third is rarely required. He then went 3.5 months seizure free but has recently had the short drop seizures return. He has a cold so we aren't sure if they're connected. We have been told with LGS he could actually regress so we are terrified now that the seizures have returned. Wondering if anyone else has tried steroids as a therapy for LGS? Or what other treatment options for LGS have worked for others? I know he is rare as his LGS has not so far effected his overall abilities but we are looking at all possibilities so we can avoid any potential regression. Any ideas, support appreciated. Being a caregiver is hard.