"Photograph of My Father in His Twenty-Second Year"

Raymond Carver’s poem “Photograph of My Father in His Twenty-Second Year” was a good poem. I thought the part “He would like to pose bluff and hearty for his posterity,/ wear his old hat cocked over his ear./ All his life my father wanted to be bold.” (lines 8-10) was good that his father was trying to be bold and the child could recognize the way his father tried to be bold and how he wore his hat. I also liked the part “In jeans and denim shirt, he leans/ against the front fender of a 1934 Ford.” (6-7)I am a little confused by the end, though. “yet how can I say thank you, I who can’t hold my liquor either,/ and don’t even know the places to fish?” (14-15) Is he thanking him seriously or sarcastically? I really cannot tell. The way I read it seems like it would be sarcastically, but I don’t know for sure.