When they get back to Earth, they will have to be put in a sort of 'iron lung' kind of contraption. It will take them weeks to reorient to being back on Earth. They will not be able to walk or see. Like long deployment submariners, when your sight is restricted to only a few feet over a long period of time, you cannot see long distances. It takes time to adjust.
After they lay in the pod for a while to get reintroduced to gravity, then they will be able to begin physical therapy to be able to walk again, to eat, to go to the bathroom, and to get around on their own. It will be a gentle long-term process.