"Hanged, as a past tense and a past participle of hang, is used in the sense of “to put to death by hanging,” as in Frontier courts hanged many a prisoner after a summary trial. A majority of the Usage Panel objects to hung used in this sense. In all other senses of the word, hung is the preferred form as past tense and past participle, as in I hung my child’s picture above my desk."
Bo appears to be using a conversational tone, bringing up one of the common misnomers of the english language just after stating that he killed himself. The juxtaposition of this extremely serious subject with a question you'd ask casually to a friend might mean that Bo is indifferent when it comes to living or dying. The decision might've been made on a whim. This establishes the pattern of a conversational tone being used for a serious subject.