BL takes no longer than osage to dry. Humidity does come into play when open air drying bow wood. Took a BL tree in early October, spit it down, barked the splits, then left the splits in a hot box for six weeks. I'm already making BL bows. As a general rule, before getting the hot box, I always let bow wood open air season for at lest a year before working. Where does your friend have it drying? Out side? Indoors?
Hank