Students shouldn’t be forced to be exposed to other people’s religion. Just because we have freedom of speech doesn’t mean it applies everywhere. 

Difficult: freedom of religion but is public expression protected? If coach works at public school, school has a responsibility wherein community should not feel that the school "publicly" encourages religion. Proselytize: NO. Quick "thanks" YES. 

It depends on what the Education Laws of that state dictate. 

Separate God from Football. Separate God from politics. Keep your God to yourself. That's where He's going to do the most good. 

Excellent podcast episode from the NYTimes the Daily on this 

A tough position to have to take, but we must be careful what we are modeling for students. A team is basically a captive audience, much like a high school class.

If his actions did not violate the rights of his students and he was not asking the students to pray with him, then pray away. 

He may pray in a private space or a house of worship. Why the showmanship for an audience unless his intentions are to influence students who attend public school, which should be free of religious rhetoric from a coach who is paid with public funds? 

WOKE-ness is Godless