Is it obligatory to wash the deceased if their body is full of sores, openings, and has flesh deterioration?

If the father dies, he should be washed if possible; otherwise, water should be poured over him. If there is a fear that he might disintegrate from the water, then the washing is abandoned, and tayammum is performed. A person who died from smallpox, burns, or drowning should be washed if possible; otherwise, water should be poured over him without touching, or tayammum should be performed if there is a fear of disintegration. If it is impossible to wash the deceased due to lack of water, tayammum should be performed. And if it is impossible to wash part of him, then what is possible should be washed, and tayammum should be performed for the remainder.