Could be tires or something too tight or sticking. Your description of the problem needs more detail. It seems you are saying that the steering wheel does not return very easily back to straight after a turn? Does it do exactly the same left and right turns? Slow to react? Like what do you mean? Steering wheel turns 180 deg and wheels don't turn? Then is sticks and truck stays in the turn when you let wheel slip thru your hands?
Put front up on jack stands and see if turning steering wheel is in sync with wheels turning. Is there some kind of "lag" between the rotation of steering wheel and front wheels turning? This is a visual test to detect a lag. Since you say no loose linkage observed, you need to observe any loss of movement between steering wheel rotation and wheels rotating. More testing and more observation needed.
Could be sort of a bump steer effect. The history of this is important to know from your Dad. Years? Months? just started recently?
Are we sure this is not a steering column bearing issue? or a king pin issue? Any noises associated with this problem?
No matter what we say or think, the bottom line is you will have to take it to a different shop. Don't go on and on about what was already done until they tell you what they think is wrong. Don't allow any work done until they tell you.
You still did not answer 1/2T?
EVERY TIME you start a post on Stovebolt you must state year, make, model, etc.
