Why did gustus refuse to tell his father what is bothering him?

Gustus likely refused to tell his father what was bothering him due to feelings of vulnerability and fear of judgment. He may have felt that expressing his troubles would make him appear weak or burden his father. Additionally, he might have believed that his father wouldn't understand or take his concerns seriously, leading him to internalize his struggles instead. This reluctance can stem from a desire for independence or the belief that he should handle his issues alone.