2004 ford explorer no crank no start

Hello! I’ve ran into a problem here recently with a family members car. They have owned the car since it was first driven off the lot. they went for a short 15 minute drive one night no over heating no running low/out of oil. come back parked the car, was no engine noise. When they went back out the next morning to start the explorer it just clicks repeatedly like the battery was dead, hooked a booster to it, same problem. at that point they sent it off to the ford dealership, they spent less then 30 minutes told the person that the engine was seased up and that they would ” love to buy the SUV.”Things are just not adding up though. I pulled the oil filer, no metal shavings, put a wrench on the balancer pulley, engine doesn’t give in ether direction.

Do these older model ford explorers have starter problems that could cause this? its the 6cyl model. only 120k miles, they have records showing every oil change. idk…. anyone got any ideas?