Complex sentence: Andrew was repeatedly told that since his father was mentally ill, then he was hereditarily mentally ill as well, and if he did not stop speaking out in defense of human rights and his father, he was told he would also be sent to the psikhushka.
Split into simpler sentences: Andrew was repeatedly told that since his father was mentally ill, then he was also mad. If he did not stop speaking out in defense of human rights and his father, they told him, he would also be sent to the psikhushka.