Here is my theory... Mom's BF is allegedly having a few unwarranted affairs around town. Mac does not like her mom dating him. She sees him for the real person he is. She spends more time with dad because she doesn't like to be around them together. She hears legit rumors of his affairs. She tells him she wants to talk to him. She leaves salon to go meet at the dock/park. (maybe she gets a coffee first. Coffee shop can't confirm or deny they served her, or maybe coffee at McDonalds in the drive thru) While waiting for him, she texts her BF. Mom's BF shows up and she starts to tell him that she has discovered the affairs and she is going to tell her mom. He says they should go somewhere else and talk and suggests taking a drive. (they get in her car) He realizes that without Mac's mom, he is nothing. No money, failed relationships, rocky marriage, etc. She is his source of money and employment. (I bet if we check back, he does countless construction jobs because of her building commitments) Without her, where is he. He realizes he has to shut her up immediately. (Maybe Mac's mom caught him cheating before and said never again?) They end up at the murder scene. (I am not convinced this is the spec house or where her body is found, I think there will be another spot disclosed) He uses something to knock her out. He uses tools from construction to mutilate her body. I am going with a jab saw. Dry wallers use them. (my neighbor is a drywaller and this tool is gruesome. I can't believe they even sell this tool. I'd panic anytime my kids would go in his garage for fear they would hurt themselves.) He is attempting to dismember her and get rid of her body. Never to be seen again. He can't take the gruesome task and decides to try and make her unrecognizable. (People has attested to the fact that parts of her body were partially removed~allegedly) When he realizes that this isn't going as planned (or not planned) he needs help. Does he possibly call the brothers that are currently incarcerated to help with he body removal? They arrive and help load the body into the back of their pick up truck. (assumption) These are the car tires he is seen washing later that night at the car wash. They follow Mom's BF in Mac's red car to where her car was found. He leaves it there to seem like an abduction. He gets in their truck with the body. They head to CB and dispose of her body where it is discovered. He knows he only as until 7 when Mac is supposed to be at her dad's for dinner. Shortly there after, family will start to wonder.
Mac's mom is NOT involved at all. She as been warned by police that he is their only POI. She is told not to talk or give any information.
This is why there was no sex.
They were not having an affair, and she was not pregnant.
Mom's BF has been questioned, failed poly and now has a lawyer.
Brothers were picked up on other charges but are being held. Have they talked?
911 calls from Mac's mom the other night are most likely sheer fear of him coming over.
Mac's mom and Dad are being quiet because they KNOW what is going on.
The end. (for now anyway!)