I've thought about how I wanted the story to end.. But the idea is not set in stone, so here are 4 of the ideas I had planned but it ain't certain.

Jerry dies.

Jerry sees Krystal about to be harmed by Jeff in his drunken haze and jumps in , taking the blow to the head. When Jeff sobers up he feels like a real monster.

Krystal and Jeff die.

While having a fight, Jeff accidentally forgets that he left the ciggarette burning and now, the house has been engulfed with flames. When Jerry gets back from one of his friends, all he sees is firemen and a burnt house. 

Jerry and Krystal escape.

Having had enough, Krystal takes Jerry away and flees from the house, she has managed to remove hr collar and now, can't be tracked by Jeff.

Jeff and Jerry arrested

After a botched murder, evidence is traced to Jeff and he is found, Jerry is taken away into custody, along with Krystal and now, they are just awaiting Jeff's trial. Jerry is sent to a ward for children to help with his disorder.

Just a few ideas, none are canon yet.