Sistani is pretty sharp
It's possible that Sistani really did have heart trouble when he went to London. Heart trouble or not, Moqtada Sadr definitely set himself up for a major bruising when he launched his Najaf gambit. Sistani's return was pure theater and brilliantly managed (T.E. Lawrence would have applauded). Sadr has since been a relatively good boy. Maybe Sadr is biding his time or waiting for new instructions from Iran. More likely, Sistani had a "frank and meaningful discussion" with Sadr.
Watch Sistani. He's the real power in Iraq.
Gary