Hemodialysis and traveling outside of USA

My husband has been on Hemodialysis for 2 years. He is doing well. We are retired, so we want to travel. So far we have traveled to 3 different states where dialysis arrangements have been made by DaVita. All three times we did not know if he had a chair until 3 or 4 days before we left for our trip. This is nerve racking since plane and hotel arrangements had been made weeks or months in advance. Is it common to get or not get your chair a few days before the trip? Do you always get a chair fairly close to your destination? We would like to take a cruise outside the US. Arrangements have to be made to be dialysed when the ship docks which DaVita can do. Anyone ever do this? I was wondering if there is a problem getting a chair, getting there and with the language. We would like to take a cruise to the Mediterrean. So language could be a problem. I would appreciate any help from anyone who has attempted traveling outside the US. I did look at Dialysis At Sea cruise lines. That is an option, but our scope could be broader if there is not a problem going off the ship to be dialysed on land.