There have been some major (overdue) maintenance projects that have caused service cutbacks on, I think, the red and orange lines in particular. I also saw just a couple days ago there were delays on my commuter rail line due to rail work.

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.