S.W.
I don't see the marriage as the most immediate issue here. I see Lana's mental health as the main issue. If what she is telling you is the truth, she has a severe case of depression and maybe more. Yes, shock treatments are still used to treat this today but only after medication and all other options have not worked. Eight sessions seems extreme, but remember, you are being told this by someone with recognized memory issues (shock treatments cause memory issues, that's how they work) and on-going mental health issues. Please take all information gotten from Lana "with a grain of salt".
I've been to couples counseling and known many other couples who have, also. Often, when someone says the counselor is "taking his/her side" it's because they don't want to hear what the counselor is telling them.
I don't know that there is anything you can do for Lana. If you have any kind of relationship with her older daughter, you might reach out to hear another opinion of what is happening in Lana's life. Otherwise, all you can do is listen and be supportive.