As pointed out, Michael is a manipulator. He uses people. They are expendable to him. He thinks that he is being like his father, but he is only mimicking his father. His resentment of Tom probably goes back to when Tom was admitted to the Corleone household. Tom's failures only add to that resentment.

"Generosity. That was my first mistake."
"Experience must be our only guide; reason may mislead us."
"Instagram is Twitter for people who can't read."