Real time help, truck won't start
 

My brother has a 2013 f 150 Harley with the 6.2 32,000 miles. A month ago we installed a K&N drop in. A week ago, it didn't want to turn over but after a few starts it did.
Today he drove from Orlando to Gainesville and as he pulled into the parking lot by the game it said low oil pressure right before he shut it off. 3 hours later it won't turn over. Any ideas??