Yes, I would bring it. For a cruise, there might be times when it would be more convenient to have the wheelchair as opposed to the rented
scooter.
What you want to do is called "gate checking." You are actually able to keep the wheelchair until she gets on board the plane. She can use it to get down the gateway and to the door of the plane. You leave the wheelchair at the door and the baggage people will take it down and put it in the baggage compartment of the plane. It's best to remove anyything that might come of or be broken off (like if she has removeable arm/foot rests, then fold the wheelchair and secure it so it won't unfold. The wheelchair will be waiting for you when you get off (it does take a few minutes to get it off though, so don't try to be the first off. )
If the plane has a closet that a wheelchair will it into (not all do), you can bring the wheelchair on board into the cabin and put it into the closet. The space is limited and if someone else with a wheelchair beats you to it, the wheelchair will need to be put in the baggage compartment.
Mobility equipment like wheelchairs or
ECVs does not count toward either your carryon or checked baggage allowance.
How do you arrange to do it?
Ask about gate checking when you first check in for your flight. They may give you a gate check tag right then, or tell you to check in with the gate agent to get one (you want to do that
well before boarding starts. Sometimes you have a choice of where the gate checked item will be returned (to the gate or baggage claim of your final destination or an airport where you chenge planes). If you have a tight connection, you may want to send the wheelchair all the way to your final destination.