That is definitely without a doubt the main reason is my suspicion that he doesn't want to have his friends ask him for money. Now the question is to what extent is he ignoring his friends? Did he block his number or get a new number altogether? Maybe he saw this as a chance for a new life, a chance to start over with a clean slate and make a new life with new friends for himself. Regardless of what his decision is and what his reasons where its rightfully his money and his winnings, & his luck! Lucky man he is for sure. Hopefully some of that luck rubs off on us for participating in this discussion ;P
He can ignoring his friends by avoids from blocking their numbers or don't wants to meet them. He doesn't wants to see his friends used him for their purposes so he trying to avoids them. His friends can't jealous with him because he can wins the money from gambling and if he avoids them, he can do that easily and will not trying to explain his reasons about that. Regardless of what happens to them, it's better his friends accept the change that he do and don't think much about that. Let's him do whatever he do and his friends can do what they wants without interfere of his lives because when someone change, no one can gets close to him, especially if that person now have a lot of money from gambling. He will thinks about his lives and don't care about other people.