Re: Affixing pre-hung door to 1950's brick rowhouse
In the old days, the jambs would have been substantial timber frames and either mortared into the brickwork via "ears" or nailed into wooden blocks embedded by the masons during construction. Either method is viable today. In your case, maybe the best path forward lies in screw-in masonry anchors. It's likely possible to carefully first shim the frame to the brick at each point of attachment and there drill (with a hammer drill) the proper sized pilot hole into the end of the brick to accept a screw ("tapcon" or "con-sert" brands) to fix the jamb. An alternative is to remove the door, and using the same fasteners attach a 2x4 or 2x6 to the masonry and then nail the door frame to that timber. But I don't know if you have the room for that. I recommend several cans of expanding foam to seal and adhere the timber bucks or the finish jambs to the opening. The foam is really best for weatherizing between masonry and wood. Don't use a high-expansion foam that will swell the frame against the door; neither do I recommend the latex foam. It has the consistency of a soggy marshmallow and will garner you no additional holding power the way a good old-fashioned high-voc rigid foam will.
Remove not the ancient landmark, which your fathers have set.