My first thought, actually.
She went from hip surgery to pneumonia to dead of cancer just in time to suck in the sympathy vote--While Berg was sniffing after the BC. Too mant co-inkydinks.
Seniors with little muscle mass often progress to pneumonia when a broken bone makes demands on the amino acid supplies. The immune system is left with insufficient resources. Maintaining muscle mass is important to long term health.
It was entirely too convenient for Obama's grandmother to pass on when she did. I'm inclined to believe her demise was "helped" along.