Hush here would probably kill his relatives more directly, but that would require possibly getting busted for it. Now, COVID gives guys like this an opportunity. If someone close to them gets infected and dies, then its all a tragic consequence of the Pandemic. It’d be difficult nigh impossible to prove he actually infected her on purpose just to get her outta the way. Because of plausible deniability and the fact there’s a Pandemic going on.
And being asymptomatic as he most likely is statistically due to personal cardiovascular health and wellbeing (as these guys bent on inheritance and wherein the inheritance would be sizable most often can afford every single method of staying in shape), he can do this trick over and over and over again.
That’s the frightening thing about this season of COVID - the people who’d love to kill people but can’t get away with it (and thus stay lawful) due to advancements in criminology and forensic evidence now have the perfect weapon and the most insidious Modus Operandi. Why go tie someone up, slash them to pieces and then drop them in a lake when COVID is out flying around?