frame coming away

Caretaker / manager of a camp conference place that need 'refreshing'

This one has me stumped
concrete floor, besser block walls the door frame on one side is good, the other side is pulling? away from the wall..

How can I secure it back to wall...dont think liquid nail would work...:D

Screw and /or pop rivet a flat strip of metal to the brick/metal frame. Push the frame back to the brick and ensure the frame remains plumb and the door will still close.