You need to speak to a local estate lawyer ASAP. If the death only occurred 10 days ago, it seems very premature for uncle to be making demands on occupancy. You may also have rights as a tenant, which would prevent you from just being thrown out. He cannot take matters into his own hands. As for your youngest child's inheritance, you and father should agree on setting up a trust with these funds, with a trustee other than father, or seek a modification of your divorce judgment to compel the funds be held in trust and out of father's potential grasp.
To questioners from West Virginia & New York: Although I am licensed to practice in your state, I practice on a day-to-day basis in Massachusetts. I answer questions in your state in areas of the law in which I practice, and in which I feel comfortable trying to offer you assistance based on my knowledge of specific statutes in your state and/or general principles applicable in all states. It is always best, however, to work with attorneys and court personnel in your own area to deal with specific problems and factual situations.
He cannot just kick you out if you have been living there for longer than 30 days. He can only evict you through Housing Court. Also you may want to contest the will.
You would be well-served to discuss your dilemma with a New York estates attorney in a confidential forum as soon as possible.
Facts are some what confusing however as my colleagues recommended, best to consult with a local attorney. If I can be of any assistance, please contact my office to set up a consultation (518.383.1182).
No one has any authority to act on behalf of the estate until the court appoints them. Even if he has a will that says the terms he has stated to you, there might be reason to challenge it or its provisions. Also, sometimes provisions need to be construed by the court. As all of the other posts, I would seek out legal counsel and fast. When someone refuses to show a document, there is usually a reaon why.