Nicotine is harder to kick than most recreational drugs. That said, I wouldn't doubt he has found opportunities to "get his head on" (who knows - maybe more than one way...).
To be honest, I don’t know why he would thank his mom for anything. She had him with a foreigner who abandoned him, then pretty much abandoned him herself. He mentioned Gramps, who was the typical white person who took over the responsibility and raised him.