We do have the amended trust doc that was provided to the bank a number of years ago by the grantor, and neither co-trustee disputes its accuracy. We are confident adding him.
I hate when parents name co-trustees or co-executors. If there is a kid you do not trust, don’t name them. And it has nothing to do with fairness. Pick a niece, a nephew, close friend who you and they trust, but don’t cop out and name multiples because you are afraid of hurt feelings or have trust issues.