Jenelle Evans‘ ex Nathan Griffith is seeking full custody of their 4-year-old son Kaiser, PEOPLE confirms.

A clerk for the Columbus County Court in North Carolina confirms that Griffith filed a motion to modify custody on July 24 — one day after Teen Mom 2aired footage of an April incident in which Evans pulled a gun on another driver for allegedly tailgating her on the highway while her 8-year-old son Jace was in the car. (The Ashley was the first to report the news of the motion.)

In the motion, Griffith alleges that Evans’ husband David Eason is a “violent person who is a danger to the minor child.”

Griffith also alleges that both Evans and Eason “have have drug dependency and substance abuse issues,” claiming that “the minor child in question, as well as another of the plaintiff’s children, did test positive for THC at birth.” (Evans has previously admitted to testing positive for THC, the chemical found in cannabis, after giving birth to daughter Ensley last year, though she said her daughter did not test positive.)

The motion alleges that Evans “has been rehab two to three times but has never completed treatment” and “is frequently in criminal trouble, being arrested in excess of 20 times.”

Griffith is seeking full legal and physical custody of Kaiser, with Evans getting secondary custody in the form of visitation.

“The above constitutes a substantial change in circumstances affecting the welfare of the minor child, such that the court should modify the prior orders and award the defendant with primary care, custody and control of the minor child subject to visitation with the plaintiff,” states the motion.

Eason and Evans did not respond to PEOPLE’s request for comment.

View photos Jenelle Evans and Nathan Griffith More

View photos Jenelle Evans and David Eason More

Last week, Griffith told TMZ he thinks the footage of Evans’ road rage incident will help him gain custody over Kaiser “because it shows an unstable environment” and “a very hectic situation.”

“I think it shows that the child might be in danger being in a hostile situation like that,” he said, arguing that Evans is “not making sound judgment to keep the children safe.”

“Overall, I provide a stable and peaceful environment and even footage shows that I’m constantly trying to take Kaiser out of a hostile situation,” he said. “I am afraid that if she carries a loaded weapon inside a vehicle and she keeps it that accessible, without a lock on it — that’s very dangerous to be around children.”