You can try and force a companion change. I believe that one of the following quests will leave you with an empty companion slot after being completed.

After completing a quest from the ones above try and wait a week or two of in-game time and than go to the place where you would normally hire them. In your case go to Windhelmand search for Calder.

There is the possibility that having loaded a safe that was and playing without installing the DLC might have deleted your followers inventory.

If this doesn't work I believe that loading an old safe will do but if you lack one there is always the possibility to try and port your current safe to PC and using console bring back Calder.Keep in mind that this is not easy.

You can try and force a companion change. I believe that one of the following quests will leave you with an empty companion slot after being completed.

Link for more follower info.

After completing a quest from the ones above try and wait a week or two of in-game time and than go to the place where you would normally hire them. In your case go to Windhelmand search for Calder.

There is the possibility that having loaded a safe that was and playing without installing the DLC might have deleted your followers inventory.

If this doesn't work I believe that loading an old safe will do but if you lack one there is always the possibility to try and port your current safe to PC and using console bring back Calder.Keep in mind that this is not easy.