What year is your hubby talking about - the 7.3 we had, and anecdotally from everyone who has had them, says they are bullet proof and that mechanics will kill for them. Ours was an 89 and, admittedly, well maintained, but never gave a minute’s trouble no matter where we hauled, or how loaded it was.
It was a stick shift, 4x4.
It is not cheap to maintain a truck, but costs less over the long term. IMHO.