Everything I've been able to find says there is no muster roll for Braddock's Defeat.
Do you subscribe to Ancestry.com? Paul and Raymond Demere are mentioned in Colonial Soldiers of the South 1732-1774. Captain Paul Demere is mentioned in a letter from Captain George Mercer to Col. George Washington. This was in the Virginia Militia. The rest of the references are in the Georgia Militia.
Found this in Revolutionary War Officers - Demeré, Raymond (Ga). Lieutenant Georgia Militia; taken prisoner at Savannah, 4th March, 1776.
You probably have all of this. Raymond Demere Sr. appears to be the father of Paul Demere. There is a will.
If you don't have this info, please contact me directly at firstname.lastname@example.org