Some shuls won't allow him to recite the Rabbi's Kaddish (Kaddish D'Rabbanan) after the Mishnayos.

Explain to them that this Kaddish is universally recognized in all Jewish communities. The Talmud teaches that the world exists because of the recitation of Yehei Shemei Rabbah in this Kaddish. https://www.torahrecordings.com/rebbe/igroskodesh/011/007/3410