AUN, may Allah shower him mercy, and give your family sabr in this difficult time. I have heard that people who pass from difficulty breathing and/or pandemics are considered martyrs. May Allah treat him as such.
O Allah, forgive him and elevate his station among those who are guided. Send him along the path of those who came before, and forgive us and him, O Lord of the worlds. Enlarge for him his grave and shed light upon him in it.
May Allah make it easy for both you and your family walaal