You have been given excellent advice to document history. As far as what documentation you will be able to procure, it's very difficult to say. You need to talk to an attorney. I know you said your uncle is an attorney & he has advised you, but I'd hazard a guess he is either not a family law attorney, or he is simply not a shark. If your uncle is in family law & doesn't seem confident he can help you, beat the bushes & find the shark in your area.
You need to get on this, particularly because of your children. The instability you describe is dangerous to all of you, and you can find yourself explaining to Protective Services workers why you failed to protect should there be an incident where they then become involved. Failure to protect would be a reason why your children could be kept from YOU, and it does happen to families all of the time. You may be advised by your attorney to get a restraining order. It may not help against someone with your DH's issues, but it will be something to be taken seriously by the authorities that you are in fact attempting to protect your children and yourself.
Your DH has some chronic mental illnesses that will require him to be in lifelong treatment. He may not have bi-polar, but there are a myriad of other diagnoses out there which may apply. You should be able to obtain a supervised parenting time order at some point, hopefully with permanent provisions that DH must prove compliance with treatment and medications and drug screens in order to maintain parenting time, supervised or unsupervised. Hopefully with those provisions in place you may be able to move to a point where he can indeed have unsupervised parenting time -- in the future.
Very best of luck to you and your kids.