The issue is how title to your mother's property was held and the source of her money. Anything acquired during her remarriage will be presumed community property. The surviving spouse is the beneficiary of community property if there is no Will or Trust. If there is a Will or trust, the provisions of those documents will control. You are entitled to a copy of any trust.
If the assets were in Joint Tenancy, those pass by operation of law to the surviving joint tenant.
Anything that was your mothers separate property and not held in title in a manner indicated above would go by intestacy 1/3 to the husband and 2/3 to the kids.
If the husband does not want to cooperate you could Petition to Probate under intestacy and give notice to husband and make him come forward.
You should consult a Probate Attorney.
The general advice above does not constitute an attorney-client relationship: you haven't hired me or my firm or given me confidential information by posting on this public forum, and my answer on this public forum does not constitute attorney-client advice. IRS Circular 230 Disclosure: In order to comply with requirements imposed by the Internal Revenue Service, we inform you that any U.S. tax advice contained in this communication (including any attachments) is not intended to be used, and cannot be used, for the purpose of (i) avoiding penalties under the Internal Revenue Code or (ii) promoting, marketing, or recommending to another party any transaction or matter addressed herein.
If your mother brought money into the marriage and it was not commingled, you have a right to a portion of her estate. However, you must be the person to assert that right in a probate court, and the longer you wait, the harder it will be to determine what you might be entitled to. Sit down with an attorney, discuss what your mother may have had, and see if a probate is appropriate to determine your interest in the estate.
As Ms. James mentions, if your mother had any separate property (which she describes) AND she did not dispoe of her estate by Will or trust and if it was not held jointly with your step-father (or in a method that passed to him on death), then you have an intestate right to a portion of her separate property. If by "we" you mean you and your siblings, the you and your siblings would split two-thirds of your mother's separate property that passes by intestacy. If you are your mother's only child, then you would be entitled to one-half of her separate property.
Please see an attorney who can get all of the relevant information from you and provide you with advice based on the specific facts in your case.
DISCLAIMER: THE INFORMATION PRESENTED HERE IS GENERAL IN NATURE. IT IS NOT INTENDED, NOR SHOULD IT BE CONSTRUED, AS LEGAL ADVICE. THIS RESPONSE DOES NOT CREATE AN ATTORNEY-CLIENT RELATIONSHIP BETWEEN US. YOU SHOULD CONSULT WITH A QUALIFIED ATTORNEY FOR SPECIFIC LEGAL ADVICE ABOUT YOUR PARTICULAR SITUATION.