where are my Olsens?

My grandmother Inga Olsen married my grandfather Jacob Kirchner in Hoboken 1906. Inga died in the Insane Hospital in Secaucus NJ at the age of 34. The year was 1918. She had 3 children Melbourne Evelyn And Jack. My grandfather remarried and I have never known any Olsen in my life. What happened to the family after Inga died? Did'nt they care about the children ? Evelyn was my Mom but I would love to solve this mystery.