If your grandmother owned property in her own name, she had the absolute right to transfer it to whomever she wished, including her daughter's son. As the property was self-acquired, neither you nor your father have any legal claim to it. However, if you can prove the property was purchased with joint family funds and not solely by your grandmother, it might be considered 'Benami,' potentially giving you grounds for a claim. Consulting a local lawyer is advised for specific guidance.