Yaakov de haan was originally a mizrachi, so it’s no surprise that avi will accuse him, a martyr, killed while on a mission from the gadol hador, as selfishly motivated.
He defected from mizrachi after seeing the sham of its ideology and the many flaws of its leadership.
Afterwards, to cover up their murder, zionists planted slanderous claims about his personal life. There’s no way that the aidah charedis would have accepted him as a member if he was involved in the things they accuse him of, which the zionists claim he didn’t hide. Rav zonnenfeld would have appreciated his help, but wouldn’t have accepted him the way he did if such things were remotely true.