It's only fair to say that George VI was landed with the job of king at very short notice and with no time to prepare. He was Edward's heir presumptive, but at the time Edward was a healthy man of only 42, so even if he didn't make a proper marriage and produce heirs, George VI's accession was going to be a long way in the future (had Edward reigned for his actual lifespan he would have reigned for 36 years). George VI also emphatically didn't want the job and felt himself unfitted for it. I suspect that he also felt himself - this shy, awkward stammerer - to be very much in the shadow of his glamorous elder brother. On that basis, it is hardly surprising that he wanted his brother out of sight and out of mind while he was establishing himself as a king in his own right - something he did very successfully, but probably would not have done as well or as quickly but for the war. Then, of course, Edward did not exactly acquit himself well between 1937 and 1945, and doubtless caused immense irritation with his petulant behaviour over HRH and money. Not really surprising if George VI, however fond he had previously been of his brother, got rather fed up with him.
Let us bear in mind that brothers and sisters do not always get on (my brother and I don't, though we manage to be civil to one another), and their respective spouses do not always get on either (should they be expected to?).
Ann