Is it permissible for a son to wash his mother who is incapacitated due to old age and uncover her awrah to do so?

The default rule is that it is impermissible for a man to view the 'awrah of an adult woman, except in cases of urgent necessity, such as medical treatment. If it is not possible to hire a woman for this purpose, then it is permissible for him to do so, while lowering his gaze as much as possible, refraining from directly touching the 'awrah, removing any harm using a cloth or similar item, and not discussing what he sees. However, if a woman is available to perform the task, then it is not permissible for him to do it.