Michael Jackson did not really have a drift between his younger sister, Janet Jackson. They both loved each other dearly. Though they used to have clashes during their life time that were partly due to property issues, work related issues, and partly due to other personal family issues.
One reason could be the child molestation trial and accusations that Michael Jackson had to deal with. Nevertheless, Janet Jackson remained with him through all highs and lows. All the other reported issues and rifts, are perhaps nothing but stunts by the news outlets so as to gain a better PR and number of views.