My Friend Married A Muslim Guy And Now Shes Depressed.... Help?

[SugarPlum]

3 years ago my best friend starting dating a guy who is older than her she was 17 and he was 26 at the time & her family disagreed because of his age and also because he was a muslim, after a year they got married and her family have basically disowned her and she is really unhappy in the marriage. She says he is never home & she thinks he might be cheating but because he is quite aggressive and verbally abusive to her she is to scared to challenge him about it.... They have a baby and he never helps her out with their son or with the housework ect.... Since shes been with him she has changed so much she used to be fun and bubbly and full of confidence but now she dresses like a 50 year old and is always miserable and never leaves the house.......... I don't know how to help her because she has been my friend since we were children and it really hurts me to see her this way.... What can I do?
The fact he is muslim is relevant because before they got married she converted to Islam so they could have a muslim wedding.... And he uses it to control her, for example saying things like ......... ''as a muslim woman it is your duty to do this''