Well, technically the "City of Boston" (read: BPDA) still owns the land, yes, that is explicitly clear from the City Assessing page for this parcel.
But, no way BPDA is running and paying for a demolition of the garage--imagine the political firestorm that would ignite! Every other developer afterwards would say, "oh, since you tore down that garage for Millennium--would you mind doing the same for this parcel we want to develop?!?"
Based on my reading of newsstories, here's what's going on:
1.) This is NOT a development project right now. This is the demolition of a structurally unsafe, condemned/blighted parking facility.
2.) Given the above, this is a highly politically palatable intervention.
3.) Because: even if the development proposal fizzles, you've still eliminated a textbook example of blight... and maybe a new park or some other nice similar community/public amenity emerges some time down the road in the aftermath of the failed development proposal.
3.) Politics aside, the developer entered into an agreement with the City that allows the developer to do the demolition right now. I'm sure they secured the necessary demolition permits.
4.) At the same time, on a parallel track of some sort, the regular development proposal remains in gestation. I'm sure we'll see headlines about that sometime in the spring.
5.) This is NOT a development project right now.
P.S. It only just occurred to me--is your brother named Waldorf?