I don't know if this would work, but maybe park north of Market, somewhere near the Embarcadero. Then hire one of those bicycle carriages to take you right up to one of the entrances for the disabled. You could drop off the disabled passenger on the Embarcadero, go park, walk back and hire the bike guy. I'm guessing $20-30 one-way, and you'll be able to move through gridlocked traffic (unlike taxi, Uber, etc.).