I just found the family on the 1940 Census in West Pullman. William is living with his wife and 2 sons in his mother's house in West Pullman/Chicago.
1940 US Census for Chicago (9th Ward), Cook Co., IL
SD 18-26, ED 103-630, SH 14-A&B
Enumerated: 11 April 1940
12423 S. Eggleston Ave.
12423 Eggleston Ave./Household Number-260/Owned Home/Home Value-$4,000/Not a Farm
Wojciechowski, Pauline - Head, Female, White, 56 yrs. old, Widow, b. Poland, Naturalized Citizen, Residence April 1, 1935-Same House, Engaged in the Home/Housework
Lindholm, Victoria - Daughter, Female, White, Completed the 7th Grade, b. Illnois, Residence April 1, 1935-Same House, Occ: Factory Worker/WPA Project (Public Emergency Work), Number of Hours Worked the Previous Week-32, Duration of Unemployment in Weeks-18, Number of Weeks Worked in 1939-34, Income in 1939-$440.00
Lindholm, Robert - Grandson, Male, White, 9 yrs. old, Single, Attends School, Completed the 2nd Grade, b. S. Dakota, Residence April 1, 1935-Same House
Wojciechowski, William - Son, Male, White, 26 yrs. old, Married, Highest Grade of School Completed - 7th Grade, b. Illinois, Residence April 1, 1935-Same House, Occ: Digger/WPA Project (Public Emergency Work), Number of Hours Worked the Previous Week-32, Duration of Unemployment in Weeks-26, Number of Weeks Worked in 1939-26, Income in 1939-$330.00
Wojciechowski, Emma - Daughter-in-Law, Female, White, 23 yrs. old, Married, Highest Grade of School Completed- 4 or 11-2 (Not Legible), b. Indiana, Residence April 1, 1935-Same Place, Engaged in the Home/Housework
Wojciechowski, James - Grandson, Male, White, 2 yrs. old, Single, b. Illinois
Wojciechowski, William Jr. - Grandson, Male, White, 1 yrs. old, Single, b. Illinois