In real life is she really guilty of murder?
1 case: the guy voluntarily shot himself, and she didn't obstruct him from going to a hospital
2 case: She kept ice at the bottom... yes. But the guy again voluntarily jumped.
1 counts as promoting/encouraging a suicide, though as Toma said, there's no proof. The only eyewitness was dead after all.
The ice is put in there as a trap with the intent to kill someone. There are eyewitnesses that can attest that the granny knows that the victim had a heart condition and that the victim was planning to make a dive into the pool. Plus the CCTV recording is pretty damning. With eyewitness testimony and the recording combined, it would be easy to prove that:
1. The ice water that melted from the block of ice was what killed the victim,
2. The granny was the one who brought the block of ice to the scene of crime with the intent to kill the victim.
So 2 should count as murder. Even if the trap didn't kill anyone, she can still be charged for setting up a booby trap (ice is considered a hazard) which is a felony.
CMIIW
Yeah I know your comment's 3 years old