Ricky, 46, was found dead at his Manchester home on 14 September.
The former world champion had recently announced his intention to return to the ring, with a fight scheduled against Eisa Al Dah in Dubai this December.
Greater Manchester police said they did not believe there were suspicious circumstances.
Speaking to Boxing News Magazine, Paul said: “The lights weren’t on, which I thought was strange. I thought he’d overslept, but it’s not unusual. People do oversleep.”
He added Ricky had arranged to go with his daughters, Millie and Fearne, to see the Gallagher brothers perform and was also planning a Christmas trip to Tenerife.
Paul said Ricky was “making so many plans with the people he loved”, adding: “There were so many things for him to live for – he was in a really good place.”
The Daily Mail reported Ricky had been “battling injury and grief” after the death of his friend David Leigh, who died by suicide in August.
Ricky paid tribute on social media at the time, writing: “We say our last goodbye to our mate dave leigh today. I wish you could have reached out to us mate. There was so many there for you. Give you a top send off today. See you shortly. Rick.”
Police said they were called to a home by a member of the public at 6.45am on 14 September, where they “found the body of a 46-year-old man”.
During his 15-year career, Ricky defeated Kostya Tszyu and José Luis Castillo and won 45 of his 48 fights.
He was knocked out by Floyd Mayweather Jr in 2007 and Manny Pacquiao in 2009, before retiring in 2012. In retirement, he became a vocal advocate for boxers’ mental health, speaking publicly about his own struggles.
Ricky’s son Campbell, 24, said in a statement: “Heartbroken isn’t the word. Everybody has always said I was your double and never a truer word said. Looked up to you in every aspect of life. Can’t explain how much I’m going to miss the laughs we had and all the good times which I will remember forever. Just can’t believe we won’t have anymore. Love you dad.”
His mother Carol posted images on social media, describing her son as her “beautiful boy” and adding: “(He was) never The Hitman to us, just Richard.”
A family statement said Ricky had been excited for his daughters to see him fight live for the first time.
It read: “We are all distraught at the events of recent days. To all our knowledge, despite his well-documented struggles, Richard was in a good place.
“He was excited for the future; his bag was packed ready to go to Dubai to promote a comeback fight and he was planning a celebration in Dubai which his beloved girls Millie and Fearne were to be the centre of. He was excited that they would see him fight for the first time in person.”
The statement continued: “He was a doting grandfather and loved spending time with Campbell and Lyla. Richard planned to spend more time in Tenerife. Richard was not alone in life or in the days before the weekend. We are all in shock at the events that unfolded over the weekend.”
