Jem Aswad Senior Music EditorCindy Blackman Santana said that her husband Carlos is “doing very well” after he passed out onstage during a concert earlier this week.The veteran guitarist was performing at the Pine Knob Music Theatre outside of Detroit on Tuesday night when he collapsed in mid-song due to heat exhaustion and dehydration, his rep later explained. He was immediately treated by medical personnel and waved to fans as he was wheeled offstage and taken to a nearby hospital.“Hi Everyone! Carlos & I thank you so much for your prayers, love, care & concern for him!,” she wrote in a Facebook post on Wednesday “Please know that he’s resting and doing very well! He was diagnosed with heat exhaustion & dehydration… it was 100 degrees on stage and 114 under the lights so that coupled with not enough water is what caused the issue.