Nick Gordon's family fear for his life.

The 25-year-old star has been spiralling out of control since his girlfriend Bobbi Kristina Brown was found unresponsive in the bath on January 31, and his loved ones are worried he won't be able to cope if the aspiring singer - who is in a medically-induced coma - loses her fight for life.

Jack Walker Jr., Nick's mother Michelle's partner who the troubled star regards as a father figure, said: ''He's out of control right now. He's hurt. He's hitting rock bottom with this.

''If something happens to Bobbi Kristina... if she doesn't pull through then I will fear for my son's life.''

Nick checked into rehab last week and Jack admits it has been ''harder and harder'' watching him try to cope with what has happened to Bobbi Kristina.

He told 'Access Hollywood': ''Every day. It hurts a lot, seeing him in pain. [Him] not wanting to go forward because he's hurt so bad... It's hard for him each day. He doesn't know if he can make it another day. It's getting harder and harder.''

Nick and Bobbi Kristina claimed they were married in January 2014, but it recently emerged they had never legally tied the knot, and Jack insists the family were as clueless about their relationship status as anyone else.

Asked if he believed they had married, he said: ''I couldn't say 100 percent sure yes or no. I wasn't there. If you say, 'I eloped,' you know, you've got to take someone's word for it.

''Everyone was told what the media was told. That they were married.''