Generally, the beneficiary designation controls absolutely but I'm not entirely sure in more convoluted situations. You may wish to contact an attorney experienced in estate contests and I would recommend contacing Attorney Curtis Shirley in Indianapolis (link below). If he doesn't know, I'm not sure who would.
Advice on this forum is for informational purposes only and should never be mistaken as a substitute for legal advice. If you are in need of legal advice, you should consult local legal counsel.
Challenging a beneficiary designation on a life insurance policy after the insured has died is very difficult. It is likely that one would need to be able to establish that the insured was incompetent, that he or she was the victim of a fraud, or other similar situation. The fact that in this particular case the insured stayed friendly with his girlfriend likely makes a very difficult task even more difficult. If you wish to go further with this before spending much money on legal fees, ensure that any lawyer you might consider instructing can first determine whether there any similar type claims in your state have been successful.
The previous attorney has provided good advice and information. Life insurance benefits are paid to the designated beneficiary on the policy and most States have laws that give a strong presumption of correctness to a designated beneficiary. In most instances it is very very difficult to successfully challenge and/or remove a beneficiary. In your situation, as much as your family would benefit from the money, I do not think you would have much of a chance for defeating the payment to Tina.
I have attached a link to our firm's Life Insurance Claims Resource Ctr which has an article on locating additional Life Insurance Policies and you may want to rev'w this. (of course even if you locate another life insurance policy, it too will pay to the desiganted beneficiary.)
Life insurance policies are paid to the beneficiary listed on the policy. Whenever anyone has a delayed or a denied life insurance claim, they should retain a life insurance lawyer to get them the proceeds they are entitled to. Here is a link for you www.InsuranceClaimLawFirm.com.
John Lassen 1-877-252-4630