If they lost a leg or an arm, what would happen to them? Assuming they survived the injury, what would they do when they returned home? Would they get money from the king honoring their service? Or were they left to fend for themselves? What jobs could they do?
I think you are (perhaps intentionally) conflating modern military service and concepts of veterancy with historical ones. If you are serious in attempting to understand contemporary treatment of 'disability' then you might be interested in the story of John the Blind, king of Bohemia.