My Marine son who is deployed right now said he and every Marines he knows stands with the President, and would do all it takes to protect him, and the Constitution.
God bless your son and your family.
Yes, the Marines actually have a part of their charter that allows for the President to use them for uses/missions chose by the POTIS:
http://www.conservapedia.com/United_States_Marine_Corps
7. Perform such other duties as the President may direct.
I don't think it is an accident that President Trump has surrounded himself with Marines.