Tonufun

My son just bought a 2013 Silverado crew cab. It has an aftermarket alarm & fob that doesn’t work. No factory fob. The doors will not lock by pushing the switch on the driver or passenger door. They all 4 lock when the truck is put in gear. I found a blown fuse associated with the door lock & replaced it but they still don’t work (now I forget which fuse it was & none have blown again). I attempted to get a new fob & spare keys but they won’t program - assuming it’s because the doors won’t lock?