DaMoshe, thanks for a good story. This is the same theme as Akeida, where Avraham has to go against his middah of chesed. For this boy, it is a test whether he never missed mincha because he is serious or because he is OCD and a show-off. You would know the answer by what he does when there is a competing need. Also, a period “from bar mitzva” and “going to friend’s wedding” may not be that long a period according to the Satmar joke about priority between a hasan and a bar mitzva – “whoever is older”. There was a similar story at the early Covid lockdown of an elderly person who never missed davening. When questioned, he said he has no problem, he is doing every day whatever is required that day.
Avira, not sure how Tanya is dangerous here, it seems to give same message. (even as I agree with your sentiment in general).