Silas was the 3rd son of Simon Ngige Wainaina and Jacinta Wangui Gatuguta ofMatunda , Kitale in Uasin Gishu, and brother to Boniface Wainaina (late),Robert Ndungu, Brian Njuguna and Sammy Ngige. He was a loving father to Joshua Prince, Zoe Linda Mary and Oliver Wainaina.

He was a cherished uncle to Nicole, Linda, Favour, Kate, Praise, Darian, Theo, Zahir and Adam. Silas was a beloved cousin to Phui, Douglas, Monica, Joseph, Isaac and Esther.

He was also a brother-in-law to Esther, Ann, and Azrah.