I have an '01 Civic.
Stock tire size is a 185/70R14 for your son's car. So you are increasing the diameter about two inches. In the rear, you should be fine, even with lowering assuming you aren't changing the wheel offset. In the front, I would suspect you will rub, but you will need to confirm by measuring. I don't know anyone that has increased the wheel diameter
and lowered that much.
I believe you are stuck on tranny gear ratio without switching to a manual. You could go with an HX CVT tranny, but that would be a bad idea. Better would be to switch to an HX manual tranny which would give you the best ratios. Likely your tranny will fail soon anyways, so have one ready when it happens (7th gen Civic trannies are prone to failure
I am replacing mine right now.).