Almost all preparedness advice quietly assumes a healthy adult who can carry a bag down four flights of stairs. Plan for the people in your household for whom that is not true.
Write down what they actually need. Medicines and doses. Equipment: glasses, hearing aids and their batteries, a walking frame, a wheelchair, a stoma or catheter supply, incontinence products. Anything that needs mains electricity — an oxygen concentrator, a nebuliser, a hoist — and what happens to it in a power cut.
Ask now what the local arrangement is. Many countries and municipalities keep a register of residents who would need assistance to evacuate, and many people who qualify have never heard of it. Your country's civil-protection authority is the place to ask.
Two people, not one. Anybody who cannot leave unaided needs two people who know they exist and where they live — because one of them will be somewhere else.
A day's supply of everything essential in a bag by their door, packed by somebody who knows what they use.
Deafness and blindness change the plan. A siren is not a warning to somebody who cannot hear it, and a written notice is not a warning to somebody who cannot read it. Agree who is responsible for telling them, by knocking.