I definitely agree that the guy in the other cage is the sultan and thus Jafar’s father. Jafar would be especially annoyed if he was cast out because of being an illegitimate child whereas Jasmine was allowed to maintain her position as princess yet marry a “street rat”. Since Agrabah is a patriarchal society, it’s Jasmine’s husband that would rule so Jafar would be pissed if his rightful position as heir went to Aladdin.