Eric, of Pogmoor, was sentenced to a year in jail last year, for dishonestly claiming £14,500 in parliamentary expenses.
It has yet to be decided if Mr MacShane will be prosecuted after parliament's Standards and Privileges Committee found him guilty of making 19 false claims totalling £12,900.
He was given a record year-long ban from parliament without pay and resigned last Friday.
The report states Mr MacShane's case was the gravest which had come to the committee for adjudication.
Eric said: "What's happened has happened and Denis has lost his career. I lost mine but I had to go to prison and get all the consequences that go with that.
"Why couldn't my case be dealt with by the commissioner? Why couldn't I be allowed to repay the money, which I did anyway, and get on with my life? It makes it a bit of a farce."
Eric said Mr MacShane was investigated at the same time as he was, but it was decided not to proceed with the earlier inquiry.
He added: "Who decides why one gets prosecuted and why one doesn't and why are some getting away with it? There are different categories - Denis has been investigated and found guilty and had a penalty imposed. You can't serve a 12 months' suspension because you can't leave a constituency without an MP for 12 months - you have to resign.
"Another MP who was found guilty by the Standards and Privileges Committee was Bill Wiggin, who was found guilty of claiming for a mortgage he had already paid off. The commissioner said he had to repay the money and that he had been a naughty boy but he's still a government whip."
Eric said there had been lots of cases of front of the Standards and Privileges Committee where MPs had been allowed to pay the money back and no action was taken against them.
He added: "The commissioner imposed a 12 month suspension on Denis, but nothing on Bill Wiggin. Some MPs have paid back up to £100,000. Denis has been done for £12,000. It's difficult to understand.
"You just get so used to these different decisions being made. Scotland Yard and the CPS are in a world of their own. No one knows who's making the decision and why.
"A lot of cases seemed to have got lost. I think the phone hacking scandal overtook it and Scotland Yard and CPS dropped the MPs cases because they had so much pressure on them."
When asked how he would feel if Mr MacShane wasn't prosecuted, Eric replied: "I wouldn't be bothered one iota. I'm still annoyed at the double standards with a lot of MPs being allowed to get on with their careers while some are prosecuted but I'm not really bothered what happens to Denis. Good luck to him."
