Q. A 5 year old child had a cold and stayed home on Rosh Hashana. He was very upset he couldn't hear the shofar, his father borrowed a shofar and blew for him some kolos to make him happy. Is that considered chinuch of children, which is permitted on Rosh Hashana after one already complied with the mitzva?
Maybe chinuch is teaching the child to blow shofar himself, and not blowing for him? Should he better have asked another older youngster, that knows how, to blow for him?
A. Shulchan Aruch (589: 2) rules that a minor is exempt from the mitzva of shofar and cannot blow to exempt grownups. However, Remoh (596: 1) maintains that one may tell a minor even if he has reached the age of chinuch, to blow during the whole day even after he has already complied with the mitzva. Mishna Berura (ibid. 3) rules that when one does not need to blow for complying with the mitzva anymore, it is Rabbinically prohibited to do so, as would be blowing during any other Yom Tov. Although, he quotes the opinion of the Taz that Rosh Hashana is different, he maintains that most Poskim are stringent.
Pri Megodim (E'A' ibid: 4) and Chayei Adam (141: 7) opine that an adult who was already yotze, may blow for them when they recite the bocho, other Poskim are stringent (Piskei Teshuvos (589: n. 10).
Mikroei Kodesh (26) maintains that an advanced minor, may blow for a younger one, however, others disagree.
Horav Shlomo Miller's Shlit'a opinion is that in our case, it would be better to have the minor himself try to blow the shofar. (His short sounds may comply with Rashi's opinion). Or have another older minor blow for him.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit'a