Mom2R&R is right...if a parent suggests something, the kid will typically reject the idea. I have three girls, ages 11, 18 and 20 (soon to be 12, 19 and 21). The eldest has finally admitted that she wished she had taken some of our past suggestions. Middle kid watches plenty of Netflix, much more than we would like. However, she does do other stuff - she'll continue her part-time job that she has had for the past year (about 20 hours a week in summer, 10-15 hours a week during school). She'll also play her sixth (and last) summer of travel softball. She heads off to college this fall. During the school year, she played a fall and spring varsity sport, and she was on the board of a non-profit...but still managed to watch a lot of Netflix.
It sounds like he does have something to do this summer - painting murals - so perhaps he might be interested in other art activities? If he likes video games, does he also like to code? Maybe could develop an app?
Does he really need the ACT prep class or will he be bored by it? If he hasn't tried a practice test, maybe have him take one. My two older ones refused to prep for the ACT (we are in an area where the SAT is favored), so they did one practice test the week before the test. Their "red book" ACT practice test scores were the same as their real test scores. They aren't off the charts, PG types, but got 98th and 99th percentile scores with only one practice test, so prep might be a waste of his time.
Maybe next year's classes have summer assignments? Some of those have been pretty lengthy, so they could occupy some of his time too.
