In the house where he lived, his grandmother is struggling.

Just 24-years-old, William Brown, borrowed her car last week to run errands. She said he stopped at a vape store in Keller.

"Bought one, got in that car, and opened it up...he popped it, and it exploded. That's when it shot across his mouth," his grandmother said.

She says the battery exploded, debris sliced across his face and lodged in his neck. Bleeding, he searched for help, and was rushed to the hospital.

When they x-rayed him, they found the stem, the metal, embedded to where to the blood flows up to your brain. The medical examiner confirmed he died.

The exploding vape pen cut the major artery in his neck damaging his brain.

"I miss him already, and knowing he won't open that door and come through it ever again," said his grandmother.

Smoke & Vape DZ wouldn't answer ABC News' questions. It is unclear which vape pen he was using, but a recent study found thousands of burn injuries and er visits in the last few years from exploding e-cigarette batteries. A death is different.

Brown was about to celebrate his 25th birthday, his family is now planning his funeral for this week and still trying to make sense of those frantic moments in the vape shop's parking lot, and how a small device could cause so much damage.