Mr Aberdein was the Socialist MSP's right-hand man through most of his headline-grabbing defamation case against the News of the World and one of the first people Mr Sheridan thanked after he emerged, victorious, from the Court of Session last Friday.
The former teacher from Orkney originally went to Edinburgh to offer Mr Sheridan moral support in his case against the tabloid newspaper over allegations of adultery, drug-taking and orgies. But after the MSP sacked his QC, Mr Aberdein flew back to Stromness, packed his suit and laptop, and returned.
The former herring fisherman, leading light in the Scottish Association of Teachers of Language and Literature, and TES Scotland columnist sat behind Mr Sheridan and looked for contradictions in testimony and legal arguments.
"It was more like literary analysis, which is what a former English teacher could readily do. I was looking for instances where the language was being used in a certain way, or there were obvious contradictions, which suggested they were trying to conceal things," he said.
As a teacher, he staged mock trials to allow pupils studying John Steinbeck's Of Mice and Men to discuss why George shot Lenny to save him from the mob.