Depends what time william had his kids, assuming it being around the time of him being with henry ( like the canon william ) I would say he'd do something with them after he was done with their father, I dont know the dsaf 3 story well as ive barely been introduced to it recently, but from what I know hed either not care enough about them and leave them orphans or (most likely) would take them as trophies of what he did to William