Edward VIII may have been fond of his brother Albert, but he seems to have disliked (and been disliked in turn) by the future Queen Elizabeth, the Queen Mother - the wife, not the elder daughter of Prince Albert, Duke of York - to such a degree that he & Wallis Simpson appear to have spread unkind rumours that the Duchess of York was an illegitimate daughter of her father, passed off as his daughter by his married wife (They even - at least in private - gave her a nickname “Cookie” based on that slander).
So far as I can tell Elizabeth, Duchess of York, and the future Edward VIII were quite incompatible personalities with very different ideas for the monarchy - in any timeline, that’s going to seriously affect relations between Princess Elizabeth of York and ‘Uncle David’ no matter when she becomes Queen Elizabeth (Especially if a Republic movement denies her the chance to be Queen, something likely to leave her mother even more Furious).