Yea, I am wondering about Katherine's health. I've not heard anything but she is older and there could be any number of health issues.
As Off the Wall (no pun intended)

and odd as MJ was & as much as we know he had "Issues', it says a whole hell of a lot that out of the huge family he came from there was only one person he trusted with his children not to mention NOT leaving any money to them.
TIS