The T is SEVERELY fucked right now. Anyone who can drive will in Boston, at the moment.
But the parent is being a bit hyperbolic. There is still a mostly functioning subway system. You can check the mbta.com website. As I look now there are delays but probably nothing too awful for someone in the city for a few days.
I'd really prefer to avoid a ride share or rental car.
Edit - it appears that it's less than a 10 minute walk from Govt Center (blue) to Park St (red). That's better than waiting for a train and taking for a single stop, right?
https://www.google.com/maps/dir/Revere+Beach,+Revere,+MA+021...