Because your son did well in the first two classes maybe some setting events triggers him to developed the behaviours you mentioned or he is engaging in problem behaviour to escape from his swimming class. You need to collect information events that are occurring within your son environment by using ABC chart. I can Email to you the chart to collect the data information and let me know after. “A” refers to the antecedent, or the event or activity that immediately precedes a problem behavior. The “B” refers to observed behavior, and “C” refers to the consequence, or the event that immediately follows a response.