Currently, there is no way to remove chromosomes from cells to cure the XXY condition.
But many symptoms can be successfully treated, minimizing the impact the condition has on length and quality of life. Most XXY men have full independence and have friends, families, and normal social relationships.1 They live about as long as other men on average.2
Citations
Geschwind, D. H., & Dykens, E. (2004). Neurobehavioral and psychosocial issues in Klinefelter syndrome. Learning Disabilities Research and Practice, 19(3), 166–173.
Bojesen, A., Juul, S., Birkebaek, N., & Gravholt, C. H. (2004). Increased mortality in Klinefelter syndrome. Journal of Clinical Endocrinology and Metabolism, 89, 3830–3834.