Corrosion of Conformity singer-guitarist Pepper Keenan has revealed that Foo Fighters frontman Dave Grohl personally paid for late drummer Reed Mullin's rehab treatment before Mullin's death in January 2020. Keenan made the disclosure during an appearance on Suicide Silence guitarist Chris Garza's podcast, describing Grohl's gesture as an act of kindness he will never forget, and it sheds new light on the support Mullin received while battling serious health problems in his final years.

Mullin died at the age of 53 following a range of health issues, including an alcohol-related seizure in 2016, with C.O.C.'s 2018 album No Cross No Crown turning out to be his last with the band. Keenan explained that despite the band trying everything to help, Mullin "just couldn't get it together," and it was Grohl, who had previously worked with Mullin in the supergroup Teenage Time Killers, who stepped in to fund his rehab out of his own pocket. Keenan also reflected fondly on Mullin's talent, calling him one of the pioneers of the crossover thrash sound, and noted that C.O.C. have used several different drummers since his passing.