He wasn't breaking in to "save his child." His lawyers even say "he took the baby because it's his child." That's not the same as "he saw his baby was in immediate danger so he took her."
If you ask me, they're all idiots and they're all responsible for the death of this child. They all belong behind bars. The mother and boyfriend for putting their child in a situation where this 8 month old could eat drugs, the father for barging in on his ex and explaining his attempted abduction of their child with "I was trying to save her" instead of the more honest "I think my ex is a **&&%^ so I took my baby."
If he had known they were taking drugs or making drugs, he should have and would have said so at the custody hearing, at which point the judge, instead of returning the child to either parent, would have been remanded to state custody until the charges could be investigated. Since that didn't happen, I suspect the story the judge heard was that the father brought his mother along on a non-custody day to barge in on his ex-wife, which was the reason for her boyfriend "attacking" his mother, and he retaliated by abducting the child. At which point, based on that information, the judge did what would have appeared correct based on the information he had: returning the child to the custodial parent and for the safety of the child, removing her from the parent who broke the law by abducting her.