James Allen Denney Sr., 48, passed away unexpectedly Tuesday, July 28, at home in Westbrook.   He was born and raised in Portland, the son of Herbert and Theresa (Portas) Denney. He was a great father and enjoyed the time he spent with his children.   He is survived by a son James Allen Denney Jr.; daughters Amelia Rose May and Natalie Nicole Denney; his brothers Herbert, John, and Tom Denney; and his sister Mary Denney.   A gathering for family and friends will be held from 1 to 3 PM Wednesday, Aug 5, at Blais & Hay Funeral home, 35 Church St., Westbrook.