His First Amendment Rights have been violated. That is grounds for a civil suit as well.
Indeed the egregious violation of First AND Second Amendment rights offers the possibility of not only civil action under 42 USCS 1983 and criminal action under 18 USCS 241/242, but an excellent possibility of charges against the school corporation under 18 USCS 1961, particularly Section 1512 (b) and Section 1513.
And, of course, the Marcum family may not be the only aggrieved parties in the matter....