What an awful situation for your family . I would definitely contact your travel insurance to see if you can make a claim @Aida-Ruiz0
it isn't cold hearted of the host not to cancel your booking. If they did they would suffer financial penalties and have the dates blocked .
you would need to cancel at your end and claim on your travel insurance.
tragic as your circumstances are you can't expect the host to be out of pocket when they held the dates in good faith for you.
you could ask if they would offer a proportional refund for any dates they are able to rebook .