Always_Ask_Questions,
“Rav Gans did not lecture the father, he addressed the child directly in a very friendly manner and lead him to make a commitment to interrupt soccer and daven for a couple of minutes.”
“so I presume the Rav knew that the father will get the message and he indeed did. He and I discussed it without the kid.”
Ok, so it seems to be exactly what I speculated. The rav wanted to ensure that the kid davened mincha. The big “lesson” to the father is his interpretation of the psak and your presumption after speaking with him about it. May I ask how the shaila was worded?