Is the prayer of an elderly, blind woman who is unable to move valid if she wears a diaper containing impurities for night prayers, due to the difficulty of her reaching the restroom?

For the validity of prayer, purity of clothes, body, and place is required. Prayer is not valid in the presence of impurity, unless the worshipper is afflicted with incontinence, or the impurity is minor and excused due to the difficulty of avoiding it.

If the worshipper carries an impurity that is not excused, knowing of its presence and remembering it, their prayer is not valid.

A Muslim is obligated to purify themselves from impurity. If they are unable to do so and possess wealth, it is obligatory for them to hire someone to purify them. Otherwise, they pray according to their condition, for Allah does not burden a soul beyond its capacity.

As for the person in question, one of two things is required of her: either to dispense with the diaper by relieving herself in a vessel, or to remove the diaper and purify herself before prayer. If neither of these is possible despite exerting effort, such as hiring someone to assist her, she may pray with the impurity, and she will be excused.