If you've got a car, head east to the Salt Lick for BBQ.
Uh, the original Salt Lick is SW of Austin, in Driftwood. A second location is north, in Round Rock, which would probably be a closer drive for him. The only Salt Lick to the east of Austin is inside Bergstrom airport, so he wouldn't even need a car to get to that one.
Stiles Switch is very good BBQ without the long drive to Driftwood or the multi-hour-long lines you get at the bigger name places like Franklin's, and it's at least north of downtown, if not exactly in "North Austin". Depending how far north OP's meeting is, there's also a location in Cedar Park. (Edit: Whoops--you said tonight, and they're
closed on Mondays. Nevermind!!)
Depending on when you arrive, catching the sunset from
Mount Bonnell can be nice. There are ~100 steps to climb to the top, so not much of a "mount", but no bueno if you're on crutches.
You could also stroll around
The Domain on the north side, which is sort of the 2023 version of Mall of America. Just a big collection of shops,
restaurants, and bars, but spread out over several blocks and not enclosed in a single building structure. Which means this time of the year during the day it's sweltering and oppressive to walk around, but by evening time it's merely oppressive. (Why did malls go out of style again, especially in the South??!?)