This is not Piloting a airline. There is no mandatory retirement age. We have 90 year olds running actively here in Arkansas with big trucks. (And General Aviation flying....)
If you can meet the DOT Medical exam etc and get that 2 year card to go with the CDL.. there is no problem.
It is really a amazing feat to be 70 or whatever it is and doing work of this nature. Im 52 soon and pretty much already am 70+ when doctors assess my skeleton with medicines to prove it. Ive done my bit. And very happy to do it too. But I will not be returning unless there is like a 6 Million Dollar Man in installed parts to replace what is worn out inside before I return to trucking.
Who knows that might be possible. We have Military blown up, installed with limbs and return to active duty and go back out to fight them some more.