First and foremost Gary is the devil here. However Lori defended her husband during his trial and tried to cast doubt on the surviving victim and what was the reason for that.
Her husband terrorised her. Physically and sexually abused her own children and she still thought it wise to let her younger baby brother go with her devil of husband to do God knows what without even warning him of his manipulative tactics and how evil her husband was. The man threatened to kill your own kids if you did not come back so what could have stopped him from killing her own clueless brother. Considering how dangerous and depraved her husband was, why did she not warn her brother.
I actually believe Tim was a rotten egg too and Lori seems to be in denial of this. Tim shot that man in cold blood and it was not even self defence and let's say that Gary lied to him and threatened him etc what was the reason he helped in the sexual assault and kidnapping/confinement of an 18 yr old girl. Tim said nothing about the kidnapped girl and if she did not free herself the torture would have continued and eventually leading to her murder and God knows how many women those 2 would have colluded together to kidnap, rape and kill.
Frankly Lori should have left way earlier. She should have never married that man. I mean she was literally warned by the pastor's wife. At least she should have left when her kids were beaten to a pulp and her ex husband showed her the photos which were evidence right there but nah her daughter had to be sexually abused for her to finally leave. He probably was shocked that she even left cause he had just done about everything to her and the kids and she had never left before. She also took way too much credit for her phone call saving Brooke.