He and his wife had 3 sons:
[Humayun] Khan, who was born in the United Arab Emirates, moved to Silver Spring at age 2. He graduated from Kennedy High School in 1996 and the University of Virginia in 2000.
http://www.washingtonpost.com/wp-dyn/content/article/2004/06/16/AR2005040207609_pf.html
....his wife, Ghazala, who taught Persian at a Pakistani college before raising three boys in the Washington suburbs;
their eldest son, Shaharyar, who was a top student at the University of Virginia and a co-founder of a biotechnology company; nor Captain Khan, who posthumously earned the Bronze Star, along with a Purple Heart, for saving the lives of his men, would have been allowed to settle here.
A third son, Omer, who works at his brother’s biotech company, was born in the United States.
http://www.nytimes.com/2016/07/29/us/elections/khizr-humayun-khan-speech.html
misc additional info
KHIZR M KHAN INVESTMENTS CORPORATION
Taxpayer ID# 30007234401
https://mycpa.cpa.state.tx.us/coa/coaSearch.do