This week Christopher's brother Sean Heiss was arrested in San Sebastian, Spain, after a European-wide police hunt. He faces extradition to the UK where he will be charged with murder.
The Surrey Comet newspaper reported detectives initially believed Sheehy had died from head injuries, but a post mortem examination later revealed the cause of death as asphyxiation.
A Scotland Yard spokesman said police had offered Christopher support through family liaison officers.
"It's taken as read that there is a family liaison officer who will work with all appropriate next of kin."
A family friend, who asked not to be named, said Heiss had struggled to come to terms with his mother's death.
"He is in turmoil," she said.
Heiss fell in love with New Zealand during a holiday with his Kiwi wife in 2009.
Christopher's father Edwin Heiss spoke about their estranged family in an interview with London's Evening Standard. Speaking before Sean's arrest, Edwin said, "It is sad, so sad."
Edwin met Sheehy in Marbella and they were together for about three years but broke up about 18 years ago.
Christopher Heiss works at The Albany bar on Auckland's North Shore.
He was at work on Friday night but friends and family requested he not be approached.
A worker at the bar said: "He doesn't want to talk about it, he just wants to be left alone."
