I'm sorry I don't know anything about Alvin's children, but I found just a little about Alvin--if this is the right Alvin. You didn't give a birth year for him:
ALVIN A KUIPERS
Birth: 01 Sep 1926
Death: 15 Mar 1994
Last Residence: 24179 (Vinton, Roanoke, VA)
SS# 366-20-1593
Issued: Michigan
Here is Alvin in 1930 with his family:
1930 United States Federal Census
Name: Alvin Kuipers
Home in 1930: Zeeland, Ottawa, Michigan
Age: 3
Estimated Birth Year: abt 1926
Relation to Head of House: Son
Father's Name: Jacob
Mother's Name: Jennie
Race: White
Household Members [all b. Michigan]:
Jacob Kuipers 29 [his second marriage] laborer / dried milk plant
Jennie Kuipers 24 [says married at age 22]
Geneva Kuipers 5 [half sister of George, Alvin & James]
George Kuipers 5
Alvin Kuipers 3-7/12
James Kuipers 1-2/12
Have you tried looking up the names of Alvin's children at
http://www.whitepages.com/9901/ and calling them to see if they are family?