How do you setup an intelligent 65 year old guy for a DUI?

He had to a) drink and b) get in his car and drive

He wasn't "set up" for that, he (allegedly) did it on his own. Oh yeah, and he was driving on the wrong side of the road.

It's not totally beyond the realm of possibility that someone saw him leave the bar (or wherever he was) and called it in. It's even remotely possible that someone had something to gain by doing that. But it's still not a set up, it's called "reporting a DUI"

Unless the ATA/RAA special operations/intelligence/assassination department employed a smokin hot young woman to ply him with booze...