Can a father legally keep the mom from getting medical treatment for a kid if the father has custody?

The kid's in early teens. The dad just got custody of the son. The problem is, dad refuses to speak the the Mom for any reason. She leaves messages about dental & dr. appts. but he ignores them. The kid has no supervision from 8pm-12am-dad works nights. He's now smoking and cursing just like dad. Last visit Mom found 2 unused condoms in his bag & when he left he hadn't used the toothbrush or toothpaste she put in his bathroom. How can the Mom care for her son? Will she have to go back to court? Can that be considered Neglect? Is the kids age a factor? Sorry it's so long.
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I think it would be considered neglect in most states but a few really don't care about kids after they are 12 Sad but true
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