Peterson of My Illinois About 1917

Looking for donald edward peterson .the only info i have is he was DC or near fairfax va in 1943. He was in the U.S Mary Met rita halsey and she had his baby. Boy named after him birthcert only says his name and place. Illinois. That is All we know. I have researched and found several donald e peterson but cant pin down He was born 1920. Baby was born in wash dc in 1944. Everyone is gone except my son eric. We had his ydna done but no petersons. What can i do next? O dont know if he was born on n illinois or later ved there when drafted. Son has finish,swedish,russian,slovenia. Wtcin geneticbavkground. Thanks so much

Update: I have found a Donald Peterson, age 10 at the Illinois Masonic Orphanage at La Grange...1930....does anyone know anything about this person. thanks