A 15-year-old says the last four years of his life have been very difficult having his mom’s fiancé, Bobby, and his 8-year-old son living in their house.

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“I am scared of Bobby's son,” the teen says. “I lock my door every night because I’m scared of the possibility of Bobby's son coming into my room and hurting me.”

The teen claims he’s seen the young boy be “very violent and destructive,” and he’s afraid the child may hurt animals, his sister or even his mom, or that their house may be destroyed.

WATCH: Woman Claims Fiance’s 8-Year-Old Son Tried To Kill Her Twice

“If Bobby’s son didn't have these problems, we’d have a good life,” the teen says. “Might sound harsh, but if Bobby could live here without his son, it would be a lot better. The whole family would have a lot less stress.”

“The feeling is that their childhood, for these last four years, has just been ruined. They have memories of being stuck, afraid, miserable, having to live with locks on their bedroom doors. No toys; they get destroyed,” Dr. Phil tells Bobby and the teen’s mom, Chrysta. “And that's no way to live.”

On Thursday’s episode, Dr. Phil and a clinical psychiatrist explain what may be causing the 8-year-old’s reported behavior -- and how his family can help him. Check here to see where you can watch.

TELL DR. PHIL YOUR STORY: Have a Volatile Teen, Parent or Sibling?

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