On Mother's Day, it's hard to get a brunch reservation; and on Father's Day, it's hard to get a tee time. So, just switch days and celebrate Father's Day in May and Mother's Day in June.
Interestingly, doing that violates Kant's Categorical Imperative, which is a sort of Teutonic philosopher's version of the Golden Rule ("Act only according to that maxim whereby you can at the same time will that it should become a universal law"). Yet, if everybody switched months, then we'd be right back where we started. But if you switch, then you're a lot better off and everybody else is a tiny bit better off.