Prithvipati Shah
Prithvipati Shah( ?–1716) was the king of the Gorkha Kingdom in the Indian subcontinent, present- day Nepal.
He was the grandfather of Nara Bhupal Shah.
John Westley
Rev. John Westley( 1636 – 78) was an English nonconformist minister.
He was the grandfather of John Wesley( founder of Methodism).
Guillaume Wittouck
Guillaume Wittouck( 1749- 1829) was a Belgian lawyer and High Magistrate.
He was the Grandfather of industrialist Paul Wittouck.
Kaya Alp
Kaya Alp was, according to Ottoman tradition, the son of Kızıl Buğa and the father of Suleyman Shah, who was, in turn, the grandfather of Ertuğrul, and the great grandfather of the Ottoman Empire founder, Osman I.
Busba Kitiyakara
"Than Phu Ying" Busba Kitiyakara Sathanapong (born 1934) was the daughter of Mom Chao Nakkhatra Mangala Kitiyakara and younger sister of Sirikit Kitiyakara, who became Queen of Thailand.
Lyon Cohen
Lyon Cohen( 1868–1937) was a Polish- born Canadian businessman and a philanthropist.
He was the grandfather of singer/ poet Leonard Cohen.
Suthawan Sathirathai
"Than Phu Ying" Suthawan Sathirathai  is the only daughter of Than
Phu Ying Busba Kitiyakara (younger sister of Queen Sirikit), thus first cousin of the current king.
She is the wife of Surakiart Sathirathai, former Deputy Prime Minister in charge of foreign affairs under the government of Thaksin Shinawatra.
She was a lecturer in environmental economics at Chulalongkorn University.
Abd al-Muttalib
Abd al- Muttalib Shaybah ibn Hashim( c. 497 – 578) was the grandfather of Islamic prophet Muhammad.
Henry Bryant (naturalist)
Henry Bryant( May 12, 1820 – February 2, 1867) was an American physician and naturalist.
He was the grandfather of Henry Bryant Bigelow.
Fujiwara no Nagara
, also known as Fujiwara no Nagayoshi, was a Japanese statesman, courtier and politician of the early Heian period.
He was the grandfather of Emperor Yōzei.

Question: Who is the maternal grandfather of Suthawan Sathirathai?