I then tried the correct spelling of the name Roosevelt and voila! I have no idea if the neighboring Browns are related.

All three families are living a #1 Rear Lucas St in 1920.

1920 Census Charleston Ward 6, Charleston Co., SC
Billy Brown Head M B 35 married b. SC Father SC Mother SC Occu: Laborer US Navy Yard
Martha Brown Wife F B 25 married b. SC Father SC Mother SC
Anna B Brown Daughter F B 7 single b. SC Father SC Mother SC
Roosevelt Brown Son M B 5 single b. SC Father SC Mother SC
Charley Brown Son M B 3yrs 7mon single b. SC Father SC Mother SC
Ida Brown Daughter F B 1yr 9?mon single b. SC Father SC Mother SC

next-door

(I found this gentleman's name very difficult to read)
Peiphis? Brown Head M B 35 married b. SC Father SC Mother SC Occu: Laborer Wholesale Grocer
Viola Brown Wife F B 23 married b. SC Father SC Mother SC
Allen Brown Son M B 7 single b. SC Father SC Mother SC
Ben Brown Son M B 5 single b. SC Father SC Mother SC
Emmie Brown Daughter F B 3yr 2mon single b. SC Father SC Mother SC

next-door

Lena McBride Head F B 25 single b. SC Father SC Mother SC Occu: Farmer Working Out
Wina Brown Lodger F B 26 single b. SC Father SC Mother SC Occu: Farming Working Out
Mattie Brown Lodger F B 24 single b. SC Father SC Mother SC Occu: Farming Working Out

1930 Census Charleston Ward 12, Charleston Co., SC
William Brown Head M Neg 55 married 1st at age 33 b. SC Father SC Mother SC Occu: Huckster Vegetable
Cornelia Brown Wife F Neg 55 married 1st at age 33 b. SC Father SC Mother SC Occu: Cook Restaurant
Annabelle Brown Daughter F Neg 17 single b. SC Father SC Mother SC
Roosevelt Brown Son M Neg 16 single b. SC Father SC Mother SC
Charles Brown Son M Neg 13 single b. SC Father SC Mother SC
Ida Brown Daughter F Neg 11 single b. SC Father SC Mother SC
Carrie Brown Daughter F Neg 9 single b. SC Father SC Mother SC
William Brown Jr Son M Neg 7 single b. SC Father SC Mother SC
Robert Brown Son M Neg 5 single b. SC Father SC Mother SC