How about taking a break till the end of summer and reevaluating then? Or let him take a break but ask him to go back to piano in September?
DS4 and DS6 both started in September. It's quite obvious that DS6 isn't in it as much as he was. It's no longer as easy as it used to be and he doesn't get to fly through the songs like before. Fortunately practicing is not an issue and he does want to keep taking piano. Our music school offers lessons during the summer and both of the boys opted out. I am glad. DS6 needs a break and I need a break from practicing with DS4.
I hope your son will come back to piano if not now then may be a year or two from now.
