May peace be unto him, you, and the rest of your family.

When (if?) you feel ready, there is an organization [1] whose mission is to support siblings, parents, and grandparents of children who have died at any age. I have been heavily active with them since losing my only child 9+ years ago. I commend them to your attention. (Once again, when you feel ready.)

[1] compassionatefriends.org