This scene was cut from the theatrical release of Kingdom of Heaven, but restored for the director's cut. After speaking to Baldwin IV, Balian meets Baldwin V.
Sadly, this boy, who would become Balwin V would contract leprosy, to the heartbreak of her mother, Sibylla. She would then tearfully kill her son by poison in his sleep to spare him a life to suffering. In real life though, he died from unknown cause at Acre.
And I think it's not included in the soundtrack list of tracks on Spotify strangely? Or at least I don't recall seeing it but I might be wrong, anyway you should be able to find it on Spotify regardless of that
probably yes ...Ridley Scott maybe thought it was too tragic for Balian's character to show the audience he may have transmitted the decease and also Balian would get sick too, causing plot holes...