I tried to find out from news aggregators and could not figure it out either.

However, taking a breath full of seawater will give you a bad pneumonitis and possible pneumonia. A normal healthy person can handle this easily, and you would cough out water before it even settled in your lungs. Older people less so.

As another person said it they apparently also had pre-existing heart problems.

You'd be surprised how it can be unclear the mode of death. If family refuses an autopsy often it can remain that way forever. Generally only forensic cases will override previous patient/family wishes regarding autopsy.