Mr Khan suffered injuries to his head when he was severely beaten at a flat in Yardley Close, Bristnall Fields, just before 1am on June 8 last year.
Damon Sehra, 23, of no fixed address, has pleaded guilty to manslaughter on the ground of diminished responsibility but denies murder.
He has also been charged with attempting to cause grievous bodily harm with intent, which he denies. Sehra has pleaded guilty to a charge of assault by actual bodily harm.
Coverage of the case:
Derek Brennan, 33, of Halesowen Road, Netherton, has pleaded not guilty to murder, manslaughter, grievous bodily harm and actual bodily harm.
The jury retired after trial judge Mr Michael Chambers QC completed his summing up on the case at Wolverhampton Crown Court on Wednesday morning.