What does the judge do out of the kindness of his heart because he feels part of tom's actions are his fault

Check out this quote from chapter 14:

"This may be my last night in the world—I must not take the chance. He is worthless and unworthy, but it is largely my fault. He was entrusted to me by my brother on his dying bed, and I have indulged him to his hurt, instead of training him up severely, and making a man of him, I have violated my trust, and I must not add the sin of desertion to that. I have forgiven him once already, and would subject him to a long and hard trial before forgiving him again, if I could live; but I must not run that risk. No, I must restore the will. But if I survive the duel, I will hide it away, and he will not know, and I will not tell him until he reforms, and I see that his reformation is going to be permanent."