There is a Charles H. Atwood that died in 1921: Atwood, C H 21 April 1921 Marion county Death certificate #253
Sometimes a name can be misread. This might be your Charles. This Charles was born in Massachusetts about 1855. In 1920 he is an inmate in Salem in the Oregon State Insane Asylum.He is 65 and a widow. That makes him too old for your Charles.
What are your records to prove that your Charles died in 1921 in Oregon? Ellie