According to the US Census listings for 1930 and 1940, John's parents, John Sr. and Barbara, were both German-born, and he was still resident in his father's household in 1930. His father died in 1936, and the 1940 listing gives John Jr. as the head of household living only with his mother, prior to her death in 1941. John Jr. and June Rupert did not appear to marry until sometime after 1940, and they are the only Bollingers buried in Kossuth Cemetery other than John's parents. I do not yet know when John Jr. and June were married, or if they had any children; June would have been no younger than 31 when they married.
ADDENDUM: June was married first to Harold Robert Mcdonald in 1925, and they appear to have had at least one or two children. By the 1940 US Census, June was living in her father's household again, listed as divorced and resident as well with her two children, Robert Mcdonald (age 13) and Thomas Mcdonald (age 10). Her marriage to John Bollinger Jr. appears to have been his first, and I have not yet determined whether they had children, either.