If you think it will be an issue I would definitely try to find another option. Could you drop him off on the Harbor side and then meet him on the Esplanade after you park and come through? Also, I would consider not only walking to the park, but the walk back to parking.
I started feeling a hot spot around 6 p.m. Then we went on Space with a 30 minute wait and my feet started hurting, then my hips and low back, all in that 30 minute wait. I hobbled back to the parking structure. Clearly I hadn't been able to prepare for 9.5 hours in the park. The shoes (with relatively new inserts) I've worn on nearly every walk for the past year (unless I was wearing hiking shoes or sandals) have never bothered my feet, but they weren't up to the task yesterday -- or my feet weren't. It was the kind of situation where I would've loved to have the tram. We rarely took the tram in pre C19, but we did sometimes take it out when we didn't feel like going to DtD on the way back to parking. I wanted to cry it hurt so bad on the walk back to the car.