What a beautiful couple and your mother-in-law looks like such a sweet woman. My heart goes out to you and your family with all you’ve been through. It’s so difficult to know what to say when someone is going through this deep level of grief.

Sometimes it helps to work through emotions by sharing with others. Support is so vital to our health. Connect has a very welcoming Loss & Grief support group that might be helpful for you.
https://connect.mayoclinic.org/group/loss-grief/
Do you have a good support system around you? Other family members, friends or a religious leader?