Yes, they sure do. I would suggest contacting Carnival Special Needs department before boarding and/or going to the maître d as soon as you board the ship to discuss his/her special needs. I've heard they are very accommodating in this regards.
Almost correct. You are allowed to bring 12 cans per person at embarkation. A lot of people restock with a 12 pack on one of their cruise port stops, during cruise. Hope that helps.
From Cruisehive :Another Rockslide in Skagway, Dock to Remain Closed for 2022:
https://www.cruisehive.com/another-rockslide-in-skagway-dock-to-remain-closed-for-2022/78411