I have had it happen to me and been one to do it myself. =/ Unintentionally. I didn't realise that i was making them feel terrible. I wonder whether those who have been that way to me knew of their actions too. But I worked on myself from what I was told I had done. Stopped myself from being someone I didn't want to be.
Of course, not everyone has the strength they need to change themselves and need a lot of support. Some just refuse to see what they are doing and see no point in change. I'd say she really needs to tell him what he is doing, if she hasn't already. Tell him that it needs to end, but she'll be there to support him through it. If he refuses to accept it or if it still carries on, it's just not a relationship worth keeping.
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