What is the ruling on a sister bathing her mentally and physically disabled brother, and cleaning him, including shaving his pubic hair, due to the absence of an alternative or financial means to bring in specialists?

It is permissible for you to clean and purify your mother and brother. Looking at the 'awrah is allowed when there is a need or necessity, while lowering the gaze and wrapping a cloth around the hand if possible. It is permissible for you to remove your sick brother's pubic hair with a depilatory or by shaving, while exercising caution, as necessity is assessed according to its extent.