בס''ד
ברוך דין האמת
I am so sorry to hear this, Mo.
But remember that just as you and your mother love your stepfather, G-d also loves him. Your stepfather has now entered the real world, the world of truth and justice and love and righteousness. The physical world that we live in is like a passing dream, an illusion. The real world is the kingdom of Hashem.
Take care of your mother. Be extra kind to her, and reassure her that your stepfather is in a much better place. Reassure her that Hashem loves your stepfather, and that He will be good to your stepfather.