Greetings

I know this may sound very stupid but i am wanting to ask anybody who works at BA T5 if you could help me out with some situation that i cant understand.

My aunt was suppose to be traveling today from EDI-LHR-GCM on BA (1433 and 253). Now on Monday (the 2nd) i know that pretty much all of BAs flights to Europe and Domestic were cancelled.
However the weather outlook for Tuesday (the 3rd) was still bad but better than yesterday. I was up till 2am my time to see if actually the BA1433 would depart today and if it did i would be pretty cert. that my aunt would be able to make it all the way.

Now i woke up this morning and checked the arrival of BA1433 and it said it arrived at 8:50ish and i then went to check the BA253 departure (which was suppose to be 9:45am) and it actually departed at 11:52am. I then thought that she would be on it and get here later than expected.
However after then going on to check my emails, i found one from her son saying that she missed the connection! I havent been able to speak with her to find out what happened or what she has been re-booked on but i am just wondering if any BA T5 staff (or anybody who may know the answer) what happened???

Was the aircraft pushed back and boarding not allowed to any other connecting passengers or is there some details that ba.com isnt telling me about the proper arrival time of BA1433 from EDI?

Anybody with information that i could know i would be very grateful!