This "Old Timer" is not your average Senior Citizen.
He is Sircan Abner, a boss in the Holy Order of Man posse.
In addition to providing buffs to the rest of the posse's abilities, he is a guardian of Relics.
This means that you have a much better chance of gaining the initiative, especially if you also have a few other Holy Order characters chipping in.
Gaining the initiative is normally important, but when you are as outnumbered as Holy Orders will be, being able to get the jump on your enemy is crucial!
Going first can help keep you alive, obviously. It's even more important, because you will likely have to take a lot of chances in positioning your forces. Holy Order don't have a lot of long range options, forcing them to be more stealthy.
After GenCon, I hope to try out a number of different posse builds. I am also working on one that includes several members of the Wayward Eight.