Crack is huge in MI, just huge, literally everywhere. There is very little education about it. They just tell you not to do it, but nothing about it, such as how addictive it is, how fast it destroys a person...they tend to preach crack abstinence, not crack education. One of the things they don't tell you is that it alters the thought processes. Not in all users, but some of them will never think the way they did before crack. I fear this guy is one of those. It's going to be hard to think like him, if that is the case.
I think the simplest answer here is that this wasn't his first fall off the sobriety wagon and she either got into his stash and died or she saw him taking money and tried to tell, and he lost his temper and killed her. I think this one is a body search, not a sold child.
ETA: Or this whole thing is a setup, but I don't think so, since I'm sure that bio dad isn't unreachable to LE and since there is no mention of him as a suspect or POI...I have my doubts.
The other possibility is that "something bad" was scheduled to happen to the mom and the baby. He left the doors unlocked, right? Why? To make it look like someone else came in and did something or because there really was someone that was supposed to come in? Men have done crazy things to avoid child support, maybe he wanted her dead, baby would have had to go too, or he would have been paying child support forever (the state almost surely would have gotten custody). But Jozlynn would have been an act of contrition, maybe. Or started off that way. She would have been too young to tell much of anything, and she never would have cost him anything, not being legally his. Maybe she woke up and flipped out and he did something to her then. Just makes me wonder if there is another scuzzball around that just dropped the ball on his end of the deal.