Hi, Have you considered that George Miller - may have gone to the USA?
searched Border Crossing Records ?
Many young men - left home at an early age - even younger than 20. to work, start a life on their own. Many did not stay in the same location where they were born - or had family - but where they thought opportunities were
Have you searched - reversing the given and middle names
The father George MILLER - passed away in 1920.
Funeral Homes take information for the Registration of Death/ Long form Death Certificate.
They may also take other information - names of other family members - to be notified etc
also cost of funeral, cemetery - casket - and pallbearers . This information could possibly still be available - If the Funeral Home changes hands - records are also transferred.
Do you have names of other children - researched through them - may lead to the information you are searching for.