Is it permissible for someone who placed drops of water in the mouth of a dying person, at the latter's request, which led to a choking that hastened their death, to inherit from their estate?

There is no harm in giving water or medicine to a sick person or a dying person if it is at their request or for their benefit. If they die, there is no responsibility upon the one who gave it, because "that which results from something permissible is not guaranteed." So, if a sick person drank or ate by their own choice and died, or if someone gave them drink for their benefit and they died, there is no liability upon that person, and it does not prevent inheritance.