I don't even know him, so I will redirect you to some of the bloggers having fond recollection of him:
M Bakri Musa: Rustam Sani - Patriot and Intellectual (1944-2008)
Polytikus: Al Fatihah (II).
Nat: Rustam Sani - The Epitome of Wisdom and Generosity
Will his blog go with him too?
Make sure you get your hands on two of his latest books. Not sure whether they are out or not.