What is the main conflict in A Prayer for Owen Meany by John Irving?

Middle-aged John Wheelwright sets out to narrate the story of his childhood in Gravesend, New Hampshire. He remembers his best friend, Owen Meany, as the boy who killed his mother and restored John’s faith in God. John describes Owen as a strange child. A tiny boy, even for a dwarf. His skin is luminous and his voice high and nasally. John remembers Owen’s love for his mother, Tabitha Wheelwright, as bordering on a crush.