The 7D2 is still great for action, especially with its fast burst and solid AF. If the lighting is good indoors, it should handle your son’s football games pretty well. chimney
That said, the R7 is a nice upgrade—better autofocus, image quality, and IBIS. If you’re missing shots or want a lighter setup with more modern features, the R7 is worth it. Otherwise, the 7D2 can still get the job done.