In my opinion, Regina abused and neglected Henry and she has no business raising him. The writers may have rewritten Regina sometime during Season 2 and then again during Season 3 and said that it is okay, but they never showed it.
Regina has never been shown to be a good mother. The writers just have characters say it. It is unearned. If anything, Henry is constantly in the early seasons trying to stop Regina from killing his family members.
I like the new Regina that they are writing now after they rewrote the character, but there is very little relation between that character and the original murdering abusive psychopath in the early seasons. The writers want us to forget about that and most of the time i do because most of the time she isn’t around children, but then she is and i just can’t.