Pat and his wife, Sarah, claim they’re scared for their family’s safety, because they say they fear Pat’s father, John, may harm them or their children.

“I’m terrified of my father,” Pat says. “My dad is paranoid and he becomes very confrontational when people do not agree with him.”

Pat and Sarah claim John is delusional, violent, paranoid and so dangerous that Pat sleeps on the couch in his living room to protect his wife and two children in the event that John comes to the house at night to harm them.

“Pat and I are on the defense all the time,” Sarah says. “My father-in-law has said to my husband and I that if someone were to wrong him or cross him, he would not hesitate to attack them with a baseball bat.”

WATCH: Why Man Says He Believes Letter He Received From 7-Year-Old Grandson Includes Death Threat

However, John says he would never hurt his son. “Pat is always saying that he’s afraid that I might shoot him or something. It’s very ridiculous,” John says. “In reality, Pat has been very violent toward me. He had me in a headlock and dislocated my neck.”

In the last few months, Pat and Sarah say they think John’s delusions have gotten worse, so they say they’ve had to cut ties with John.

“My wife and I became especially alarmed when my dad took my 7-year-old son’s thank you letter that was written to him as a direct threat on his life,” Pat says. “My father took a combination of things in the letter that to him spell out that my wife and I were going to kill him.”

WATCH: Man Says Daughter-In-Law ‘Stole’ His Son, Filled His Head With Evil 

Desperate to help John and rebuild their relationship with him, Pat and Sarah turn to Dr. Phil for help.

“These delusions scare the living daylights out of both my wife and I,” John says. “I have been forced to cut him out of our lives because we do not know what he’s capable of doing. We are terrified of him.”

In the video above, John tells Dr. Phil why he feels threatened by his son. And, on Monday’s show, Dr. Phil examines the letter John’s 7-year-old grandson wrote to him and why John believes it includes a death threat. Check here to see where you can watch.