college sports - and national teams - routinely require cardiac testing. As I wrote a lot either upthread or on a different one (it was several weeks ago), some countries require cardiac testing for all youth athletes (even non-elite).
if your child is playing elite athletics she or he should be cardiac checked at least once, if not periodically. Certain conditions (like HCM), while not frequent, are not rare and can resort in sudden cardiac death. This is independent of covid.
if a college sports Doc is reporting this, it is likely he is quite aware of the generalized risk (which is documented as being far lower rates but still not insignificant and should be watched if you have an athlete who has recoveredfell from the flu)