Nick -I think I am in the same boat, so to speak - my cabin door assembly was fine, until this year when I came back from MV in some nasty stuff - the door frame popped part way over = the door was open at the time, my son popped it back into place with his fist and closed the door - one of those spur of the moment things under trying conditions - so far it hasn't popped again, but I know the upper left corner of the frame is weak/cracked/broken, and needs to be looked at.
I'm a little uncertain that you and I are built the same way, though - my cap/foredeck/dashboard drops down and then stops, on each side of the door I have large wooden panels, formica covered on the outside, that drop down to just above the footrest area of the floor/inner liner - there are 4 bolts, at both top and bottom, at the top they go thru the glass, into this wood panel - I believe with t-nuts pressed into the wood on the inside. On my boat, with any rough water conditions, the top set of bolts on the left side tend to loosen up significantly.
I have to check the condition of the t-nuts - they are under the inside cabin carpet covering, but if okay, I was thinking of just loc-titing the bolts into place, too keep them from loosening. I believe these two wood plates, either side of the cabin door, lend significant cross-wise - anti-torque stiffness to the hull-top structure.
I think you can see what I have, here -
Don't know if that helps any - but the door frame is only going to react to what is happening with the underlying structure, so that's what needs help...
or just stay out of the really rough stuff... yeah, right
Bill