saying "yes" is not consent

I recently found out that a  friend has been having lots of problems in her marriage. One thing concerns me the most, is that she has told me how she has been having sex with her husband without any desire. She just lays there waiting for him to finish. She doesn't lube and it becomes painful. He gets it done and goes to sleep. I told her that is abuse. She then reply that how could it be abuse if she's married and says 'yes' to the act. 
I want to say that, it doesn't matter if you say yes, when you truly don't want to, when it actually hurts you and at the end of it you feel like trash. 
It sadden my heart to hear someone close is going through such thing. But all I can do is be there for her, reminding her that she has immense  value. 
Sex shouldn't be physically or psychologically forced. He doesn't beat her, but he does hurt her when doesn't care for her feelings. If you are going through this too, please know you are beautiful and you should never feel obliged to have sex. 💔