I really wonder about him too and how much he really knows. He was the first one she called after turning her phone back on. And she also stayed with him on her way to Mesa to kill Travis. Who stole the gunfor her while she was out with her sister? And how did she retrieve it from them? Jodi says she had an alibi for the theft and no one had really questioned it, that I remember. He seemed overly supportive of her, willing to lie, if she needed someone to vouch for something she'd said, she'd call on Matt, with the seeming knowledge that he'd go along with whatever she said...
BIt I'm just spitballing.