I assume Charlotte has passed away, seeing as she didn't come with Wilson. And I'm pretty sure they referred to her in the past tense?
Actor ages mean nothing in voice acting business... Several of the kids in Odyssey are voiced by adults now, and Andre Stojka is younger then the actor who plays Jason.
As for him starting a new job at his age, Wilson said he had been a traveling missionary for years, and now had become a pastor. I would assume he's retiring (mostly) as a missionary, and settling down to become a pastor. Even if he is old, i don't see it as unreasonable.
We all know how corrupt Whit is... I assume he heard his brother-in-law wanted to settle down and become a pastor, so Whit got rid of the old pastor and basically just hired this new guy (who just happens to be a relative :0). #headcanon
The "Ave" reference was so obvious. It came across my mind Jack would be there too, but the name "Al" went over my head. I thought this was Whit's direct brother because Wilson said something like "I annoyed my older brother by being a stuck-in-the-mud." Turns out I heard that wrong or something, but Wilson actually was his brother. =p Since it was Chicago, I was afraid the old friend was Richard Maxwell, but thankfully that didn't happen.