'96 Classic Rear Bedroom Cabinet Separation

We have a 1996 Classic Excella 1000. We appear to be experiencing some separation of the rear bedroom cabinetry from the street side wall. It is unclear to me whether or not the upper wall brackets were ever fastened to the wall (no screws or rivets now) and there is a 1/2 inch gap between the lower wall fasteners (screws) and the wall. Is flexing of the wall the problem and should these fastenings be connected and if so what method is best?



Thanks in advance for your thoughts.