Hi, my son uses a wheelchair so I hope some of my points will be useful.
Embarkation Day: You can ask for wheelchair assistance ( this is where a staff member pushes the wheelchair user through check in and on to the ship) but consider if you need it. On our last cruise, May 2022, people were waiting up to 2 hours for wheelchair assistance.
Theatre: There is wheelchair places at the back of the theatre. These space are for people who are either wheelchair bound or just want to sit in their chair's. Normally only 1 person is allowed to sit next to the wheelchair user. If you all want to sit together the other family members can sit on the back row in front of the wheelchair space.
Port Days: There is always a staff member by the gangplank to push wheelchairs users on/off the ship. Depending on the steepness of the gangplank we sometimes push the chair ourselves particularly if there are other chair users waiting.
Lifts: You can struggle to get a wheelchair in to a lift/elevator at busy times (end of theatre shows etc).
My advice is don't let anyone who gets impatient wait with the wheelchair uses.