William Robertson, 42, was found guilty of murdering Joseph Kidd, 44, in September 2010 at Tarfside Oval, Cardonald, while a jury convicted Margaret Robertson, 43, of the lesser offence of culpable homicide. A second man, Alexander Thomson, 39, was also found guilty of murder.
The attack occurred after Margaret Robertson alleged the victim had “tried it on” and persuaded her brother to “deal” with him.
Mr Kidd was punched, stamped on or kicked, suffering a fractured skull, and was abandoned to die in a stairwell.
The trial judge said it was a vicious attack, and jailed William Robertson and Thomson for life, with a minimum term of 12 years.
Margaret Robertson had taken part by “kicking into” the victim, and she received a 10-year sentence, of which she might have to serve only half.
The Court of Criminal Appeal in Edinburgh rejected claims that the brother and sister had suffered miscarriages of justice, and ruled that their convictions should stand.