Поставьте 's или 'es там где это нужно
His family/surname/Nikolayev
His dad/name/Vladimir
His mum/favourite pop stars/ The Bee Gees
His brother/name/Voctor
Oleg/favouritw pop gtoup/Franz Ferdinand

1) His families surname Nikolayev2) His dad`s name Vladimir3) His mum`s favourite pop stars The Bee Gees4) His brother`s name Victor5) Oleg`s favuorite pop gtouo Franz Ferdinand