The 27-year-old believes the 'Rehab' singer is strong enough to kick her addictions to drink and drugs and says he supports her marriage to Blake Fielder-Civil.
He said: "Blake has a rocky past, but she's chosen to be with him and I have to stand by that.
"We had a long chat. She's very level-headed, believe it or not, even though she's had some problems. I'm confident she doesn't need to go back into rehab. Amy's not capable of doing anything awful. I feel confident she is fine."
Winehouse’s father-in-law Giles Civil recently urged fans to boycott the singer's records in a bid to force her to take action over her problems.