The World Federation One Stop Fiqh

Ruling 549

Those who are maḥram can give ghusl to one another, whether they are maḥram by being biological/blood relatives – for example, a mother and a sister – or by way of breastfeeding, or by marriage. Except for the private parts, it is not necessary to cover a corpse and give it ghusl from under the cover, although it is better to do so. However, based on obligatory precaution, a man can only give ghusl to a maḥram woman when he cannot find a woman who can give ghusl to her, and vice versa [i.e. a woman can only give ghusl to a maḥram man when she cannot find a man who can give ghusl to him].