When Ivan the Terrible became seriously ill in 1553, Viskovatiy was the first one to propose to the "tsar" to choose a successor. He was also among the first to support the nomination of the young Dmitry Ivanovich. In 1554, Viskovatiy was appointed a member of the "boyar" investigation committee regarding Prince Semeon Rostovsky's treason. That same year, Viskovatiy had to appear before the ecumenical council of the Russian Orthodox Church because he had been influenced by Matvei Bashkin's heresy and had drawn other people into accepting it. The council treated him with leniency and inflicted a three-year penance upon him. In 1563, Viskovatiy went on a diplomatic mission to Denmark to hold negotiations on Livonian affairs; that was the time when tensions between Denmark and Sweden were building up towards the Northern Seven Years' War, in which Russia did not take part, but was a very interested observer. In 1566, Viskovatiy took part in the "Zemsky Sobor".