Lewis, who is from New Orleans, spoke to FOX 8 after the couple was gunned down in their car in a parking lot of a New Orleans East apartment complex.
"A loving, caring guy,” Lewis said of his wife's brother, Lionel Delpit III, who was murdered along with girlfriend Breon Stewart. “All about his family, you know, gave his life to God. Anybody who ever knew him knew he always kept a smile on his face."
Delpit was a Mardi Gras Indian chief and the son of the well-known Big Chief of the Black Feather Mardi Gras Indian tribe.
Police have classified the murders as homicides. No arrests had been made yet as of Friday.
Lewis, who is active in the community through his charity foundation and football camps, has often talked about the need to stop the violence in New Orleans.
"The message that's the biggest thing [is] to show our younger brothers that we can get along without guns, we can do positive things,” Lewis told FOX 8. “And that's something that [Delpit] tried to preach."
Lewis was placed on season-ending injured reserve last month because of a hip injury.