Peace Pipe - S2-E5
Other mistake: When John and Roy are up on the scaffold with the injured man during the sniper fire, from the time they unfurl the large tarp and tie it off to the beams the sniper fires zero shots at them, zip, but later at the station Chet asks John, in all seriousness, if he got a good look at the tarp before they left, and tells him that the tarp looked like Swiss cheese due to the sniper fire.
Answer: I believe you are speaking of the old man, Mr. Wilson. He's played by J. Pat O'Malley.
Bishop73
Correct, it was J. Pat O'Malley...he also played the grandfather with his grandson when their rocket exploded, and also played "Old Bill" in the episode with Ann Prentiss, where Gage saves the little girl from the burning tree house, and her mother falls in love with him.