I think he feels a lot of anger towards his father who treated him very badly as a child.

anger 是名词，表示"愤怒、怒气"的情绪状态。这个词来自古英语，与表示"痛苦、悲伤"的词汇同源，在现代英语中特指因受到不公正对待而产生的强烈不满情绪。