It is also possible that your ancestor named Louis Hansen has been confused with some other. The Louis Hansen who served in the G 3 IL Infantry in the Spanish-American War is a pensioner. You can see his pension card on the Index to Civil War Pension Files at ancestry or familysearch. Spanish-American War pensioners were included on that index, even though it doesn't come right out and say so. SA War pensioners have a tiny handwritten "s" on the pension card after the word "invalid".
The soldier who served in the G 3 IL Inf applied for pension in March of 1922 while living in the state of Michigan. There are about 5 "Louis Hansen" on the microfilm of pensioners, and maybe more who served and were not pensioned. You might want to check all of them and make sure which one is yours before ordering a pension file. I didn't look at all the cards to see who was CW and who was SA. The pension file at NARA would certainly give you a positive ID on the soldier one way or the other.