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If he opened the business prior to their marriage then it is his, but if he opened it after the marriage it is part of the marital estate. California does not necessarily split things 50/50, but looks at an equitable division of the estate so he may get the whole business and she might get the house, for example depending on the value of everything. He may not have authority to move all of the business to you at this point without her consent as it would be marital property.
Unless you have a stock certificate or some proof of the same, then it would be hard to enforce, if something unfortunate were to happen to your Dad.
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