Amy Winehouse may commit suicide if her husband dies from a drugs overdose,her father-in-law has claimed.Giles Civil believes the troubled singer - who overdosed on an alleged cocktail of drugs, including heroin, earlier this month - and his son Blake Fielder-Civil are on the verge of killing themselves through drugs and fears if one of them dies the survivor may take their own life.Giles told BBC Radio 5 Live: "They're very close to the edge. If one dies through substance abuse, the other may commit suicide."His wife Georgette Fielder-Civil also fears Amy and Blake - who were pictured splattered in blood after a furious row last week - will die through drug abuse, saying: "I think they both need to get medical help before one of them, if not both of them, eventually dies."Giles has no doubt in his mind Amy, 23, and Blake, 26, are serious drug addicts and regularly use cocaine, crack cocaine and heroin. He claims the pair are still in denial about the severity of their addictions. Giles explained: "Georgette and I both believe that they are drug addicts,and they don't believe they are. I think they believe they are recreational users of drugs, and they are in control, but it seems to Georgette and I that this isn't the case."They are going through abject denial at the moment. They don't see themselves as having a problem and they are quite aggressive in defence of themselves."Giles also revealed the couple took drugs at the Fielder-Civil family home after he and Georgette asked them to look after their two teenage sons, aged 13 and 14, while they went out. He said: "We wanted them to know that we respect them, but never again."They both took drugs in the other room but it was clear to the boys what was going on."The boys know what's going on, because we sit and talk about it at home as a family, but it's very black and white to the boys. They think if Blake wants to give it up then he could."Meanwhile, Amy's dad Mitch thinks his daughter and son-in-law - who have already quit rehab twice - will have to hit rock bottom before they decide to quit drugs. Mitch said: "The only way out of this is not sectioning them, not locking them up. At some point they are going to reach rock bottom."