1) Mourning.Like we've all be doing. Grieving the loss of such a great man. Acknowledging the pain and wrongness of death.
2) Comforting.Giving comfort to one another, especially Heather and her children.
3) Acknowledging God's an even greater General, with an even greater strategy than ours.Like us, Habakuk wrestled with what he saw as a bad situation where God wasn't doing the right thing. He came to see how God had a well thought out plan. When things seem to go all wrong, God uses these things as part of his master strategy to defeat evil, benefit us in the long run, and glorify His name. Whilst's its hard to see how God will bring good out of Mike's death, we have other examples that help us understand the concept.
David Brett for example, died whilst trying to climb a mountain in Australia. This was a tragic loss, with probably no immediate benefit. However, the people searching for David's body discovered a baby's jacket that was crucial evidence in the famous 'dingo' case. The discovered jacket revealed that Michael and Lindy Chamberlain had not murdered their child. A great miscarriage of injustice was undone because of David's tragic death.
Jesus' disciples, the generals of the early church were all persecuted and died, some at an early age, yet the church continued to grow at an incredible rate, spurred on by the examples of these saints.
We lost one of our greatest generals, but we have an even greater general running things from Heaven.