Good points from Wakeup.
Just one thing I want to suggest - do you think he could have depression? Has he always been lazy or is it just after the accident? It's just that the physical restrictions following a significant accident can put one in a depressed state.
Sure, he could be just lazy, but clinical depression can remove all of one's motivation. If so, addressing the depression would be the first step towards fixing the laziness.
Never regret anything that has happened in your life. It cannot be changed, forgotten or undone. So, take it as a lesson learned and move on.