Who is Ibn Yussuf from The Haj and what is their importance?

Ibn Yussuf lived in the town of Fakim. He owned a press that made good olive oil and people, both Arabs and Jews, came to him with their crops. Yussuf followed the advice of the People from Shemesh, who helped him set up an olive oil business, with them doing the marketing. Yussuf also functioned as an information source for Gideon Asch and the Haganah and provided the information about the attack on Tabah, which allowed them to defeat the Mufti's men.