What's your opinion on Théo Lefèvre? (Prime Minister 1961-1965)

I'm currently looking into Belgian prime ministers (very interesting!), and he (Lefèvre) caught my attention, particularly because he governed for four years (which is unusual for belgian prime ministers) and apparently carried out many social reforms. However, I can hardly find much more information about him. More importantly, I can’t seem to find any real opinions on him. That's why I wanted to ask this here.