Myself (and dozens of friends, all pilots in Qatar Airways) had brought parents and in-laws for the past few years, and majority of them being above 65 years-old.They even can extendtheir visa for months, as long as they do medical after arriving. Of course treatment here depends on looking/nationality/language, this is not new. I suggest you get all possible documents/papers, go well dressed to Immigration and don't take the first no as an answer, sometimes the guy next door give you the opposite information. Good luck.