Quote From: gloriousWho refuses to help them self? 
I am living with a family member that has been diagnosed with major depression and OCD, this person refuses to accept help or even seek help, but then expects everyone to literally walk on egg shells, accept their verbal attacks on us since they refuse to be medicated and we have to be VERY careful of everything we say and do. It is utterly exhausting. I am completely, mentally, emotionally and physically tired from how over sensitive this person is and how they are refusing to get the help they so desperately need. 
Is there anything that I can do to assist them in getting the very much needed help they require? 
Thanks. 
First, I would like to say that I suffer (and, yes, it is suffering) from major depression, OCD, borderline personality disorder and other disorders that I am still being diganosed with. Sounds like the person you are referring to may also suffer from borderline personality disorder or some kind of personality disorder.
Until your family member accepts the fact that he/she has a mental health problem and seeks help, there is nothing you can do other than offer them love. Also, your statement isn't clear if you live with them or they live with you. If you live with them and can't tolerate their disorders, then move. If they live with you and you don't want to make them move, like I said before, offer them love and try to be understanding. Have you done any research on major depression, OCD, or other mental health problems? The internet is full of information and insight on what this person may be going through with their inner self.
Verbal attacks - been there and done that myself. Many times I have been on the giving end of verbal attacks to not only family members but strangers, co-workers, supervisors ... doesn't matter who it is. I realize the verbal attacks were not necessary but it is something that I can't control. And the worst thing the receiving person could do was say something back.
A lot of times, people who have depression just want to be left alone - literally, alone. I know I do. When I'm having a bad time with a depression attack, I don't want anyone saying anything to me, don't want to go anywhere and don't want to be around people. And this may not be the case for everyone who has depression.
Depression of any kind is a complicated disorder. It's hard for doctors to understand, people who don't have a depression disorder to understand and hard for the person who does have depression to understand.
This may not have helped you any, but if you're wanting to try to help, do some research as I suggested before.
Good luck and I hope your family member realizes soon they do need help. The quicker they receive the right kind of help, they better they could feel and others around them.
A last note, medicines don't always work. I take two different anti-depressant medicines a day and still have anxiety attacks, panic attacks, big time depression and it hasn't helped my personality disorder at all.