Hello fraidycat
You're getting a 'changeback' reaction - pressure to conform, so that people can continue to use you for whatever they have become accustomed to using you for. It's actually rather easy to tell when this is happening: look to see what is being offered to you, really, and compare that to what is being demanded of you.
By the way, mental illness can be an excellent reason to abandon your family; it depends on the illness, and it depends on the family. There are non-mentally ill families [and parents] who also merit abandoning.
Consider a daughter, for instance, whose mother has repeatedly failed to support her - choosing instead to favor an alcoholic or battering husband, or even an incest-perpetrating husband. Such things happen all too often, sadly; mothers of incest victims are often remarkably unwilling to see what is going on, and to take even the most elementary, no-brainer measures to protect their children. You'll also see no shortage of newspaper stories about small children who are beaten, sometimes even beaten to death, by their fathers, their stepfathers, or their mothers' latest boyfriends. Quite often the mothers of these children sacrifice their child's well being in order to keep some illusory 'peace' for themselves.
Has such a daughter ever had a mother in anything but the most basic genetic and biological sense? If they manage to survive to adulthood, many of these children decide to cut their losses, and it's hard to blame them for 'abandoning' a 'family' like the one they have had.
Basically, it sounds as though your cousin is abusing you, ferociously, here. And... I hate to say it... but your cousin does not sound like a recovering alcoholic at all, based on the behaviors you describe. The business of:
-provoking arguments for no apparent reason other than that she enjoys fights
-criticising anyone who sees the dysfunction and points it out as though THEY are the problem, rather than the dysfunction itself
-trying to force you to be loyal to a system [family] that has shown you no loyalty in the past and won't in the future [not unless they change. Does that look likely?]
-ignoring your points, criticising you, putting you down, while trying to convince you that this is loving behaviour because she 'loves' you --
This is all classic active [non-recovering] alcoholic mind gaming, abusive variety.
I say this with some concern, because brave recovering alcoholics on this site have been very honest and forthright about the thing they are fighting, and I don't want them to feel shamed in any way. But I suspect that honest alcoholics, in honest recovery, will be among the first to agree with the characterization I've presented here of how an alcoholic who is not really recovering plays head games with anyone and everything...
Well, if your head is spinning after reading this post I won't be surprised. There's a lot going on here, but there's a huge amount of head gaming, blaming, shaming and other things going on with that cousin of yours, and the rest of the family as well, it seems like.
Hold fast... remember, there are facts. Some things really are true. Get a copy of Patricia Evans' book The Verbally Abusive Relationship, read about how verbal abusers constantly distort reality, and change their arguments, and even contradict themselves just to keep their targets off balance. Look up 'gaslighting' - you can do a search on this site, even, to find posts about it. And if the only thing you can think of to protect yourself right now is to minimize contact, don't be ashamed of that. Be proud that you are protecting yourself - with whatever armor you have available.
Hang in there... hold fast.
((((((((((fraidycat))))))))))