Complex sentence: In parliament, he continued what had become his mission: educating the Dutch citizenry on colonialism, using in his speeches also confidential government information sent to him from the Indies by his friend W. Bosch.
Split into simpler sentences: In parliament, he continued what had become his mission, to educate the Dutch citizenry on colonialism. Van Hoëvell used in his speeches confidential government information sent to him from the Indies by his friend W. Bosch.