Probably depends on why the patient is azoospermic, but FSH has at least been reported to improve semen quality in men with the FSHB-variant and ongoing spermatogenesis.
Ferlin A, Vinanzi C, Selice R, Garolla A, Frigo AC, Foresta C. Toward a pharmacogenetic approach to male infertility: polymorphism of follicle-stimulating hormone beta-subunit promoter. Fertil Steril. 2011 Dec;96(6):1344-1349.e2. doi: 10.1016/j.fertnstert.2011.09.034.