Timing chains is suppose to last as long as the car. It's not a wear item.
Read the owners manual, Ford has a maintenance schedule listed for the motor.
Timing chains last much longer and many more miles as you and others know... sometimes you can tell by flooring it on freeway ... and the engine will catch then surge a little ... this is well before the gov speed control or high r.p.m. sincer kicks in
Most of the time the timing chain and sprockets don't need replaced until the engine needs rebuilt. However, with 200000 miles on it, your getting some wear on that engine. You can change it if you want to, but I imagine you'll be lookin at some more costly repairs a little later anyways and you can change it then if you decide to keep that motor. Sometimes wear can cause the chain to get too much slack and jump time. Then it is critical that you change it. If you don't it can trash the motor if it comes off. The belt is changed by inspection. If it looks dry cracked or is coming apart, change it. The timing chain is difficult to change. You have to pull the harmonic balancer as well as remove the belt, radiator, and timing chain cover. New seal and gasket is also a good idea. DO NOT crank it over with timing chain off. Other than that it's not too bad.
Timing chains usually last for the life of the engine. Because of that, some manufacturers went to timing belts saying that they are quieter. My opinion, they went to timing belts so they can charge the car owner $300-$500 to replace the belt. Simply a profit motive.
If your dad's engine has a chain, nothing to worry about.
When do you change timing chain and timing belt on a ford expedition V8?? My dad has never changed them and I told him that he probably needs to already because it could be dangerous if he keeps driving it like that. The truck has almost 200,000 miles. And he has never had any problems with the engine.