Sorry to hear your story, ours is very different. I took my 13 year old for his first ever trial on his BSA Bantam and found Somerton Classic MCC who ran 3 beginners trials. The best thing ever, very helpful club members who helped him at ever section and came and talked to him. He loved it and we have now done the third and final event and he is hooked.
The club run a 'C' route at events for him and others who just want to ride or are no good - yes, like his Dad. Come down for a weekend and do their events. Bath Classic MCC also do the same. The Classic and Twinshock clubs seem to understand what riders want.
Hope your son comes back for more.