The 56-year-old elder son of ex-president Ong Teng Cheong, Mr Ong Tze Guan, has been reported to be taking his sister-in-law, Madam Wang Yi Yi, to court over an award-winning Art Deco bungalow in Dalvey Estate GCB Area near Botanic Gardens. This comes about a year after he settled a dispute with her husband, Mr Ong Tze Boon, who is.