My ex was deported in 2004 for a white collar crime he committed. Can he obtain another visa to come back and see his daughter?

Your ex may be able to apply for a visitor visa. Whether he will be eligible and, if so, the process involved will depend upon more information about his criminal history including the crime for which he was convicted and the sentence imposed. Assuming your ex is eligible to apply for a visa with or without a waiver, he will need to be prepared to demonstrate he is a changed man and has strong ties to his country. He should consider speaking to an attorney about his eligibility.