My son died intestate recently. He was twice maried and twice divorced. He has a minor daughter by 1st wife. While married to wife # 2, I gave him $20,000 cash to purchase a buildiing for his business (Auto Repair Shop). Now wife # 2 wants "her half" of the buisiness. Her name is on the deed to the proberty because the lawyer told him since he was married, the wife's name had to be on the deed also; but the business was his before they were married. Their divorce does not mentiion anything about separtion of property. JDoes she have any rights to this property if I gave it to him as a gift?

It doesn't matter if you gave it to him or sold it to him. It was his and he in turn gave half to his wife at the time. It is half hers and half his estate's.