Hi,
I have been using expanding foam to attach woodwork to masonry for 15 years with great results.
There are two steps for the process, access points and bracing. You need to brace the woodwork exactly in position so that the expanding foam cannot warp/bow the material into an unsightly or, in the case of window and door frames, an unusable state. Some woodwork has enough gap around it (missing plaster or pointing) to admit the applicator straw for full insertion of foam. Other times 1/4" holes will need to be drilled, in the case of a door jamb, I'd drill every 16 inches.
For your door, I would close it and see that it fits against the stops for good closure, then shim every 16" so that the gap margin is established or maintained evenly all around. This might involve a dab of glue to keep the shim secure. Then, on the outside of the jamb, space bars to trap the frame against the brick. Then foam it. It will stay firmly in place until doomsday.
Casey

Casey- Thanks for the suggestions. In this case, the part of the jamb that has separated from the masonry/wood stud behind it is protruding out about 1/4 inch (which makes the jamb not square). I'd like to just attach this separated part of the jamb back to the masonry/wood stud so that it's no longer loose and is square again. If I use expanding foam where it's separated, the jamb will still be out of alignment. Do you think it's possible to just drive a long screw through the jamb to fix it back to the stud, or do I need to use a masonry screw? Thanks in advance!

Polyurethane caulk.