You didn't give any dates, so I have no way of knowing when your William Mulina was born. I did find a William Mulina who was born ca 1927. He is listed on the 1930 Washington Parish census. His parents were Loyd Mulina [bn ca 1890] and Edna Jane Cox [bn ca 1895]. He has many siblings. If you think this is your William, I can furnish a bit more information. This William may not be old enough to be your grandmother's grandfather.