The actor announced his decision to leave the cobbles in April last year and fans saw his legendary character Jack Duckworth pass away following a short illness at the end of 2010.
In a new interview with the Daily Express, Tarmey has spoken of how Carl was diagnosed with an aggressive tumour in 2009. He immediately started receiving treatment, which has led to the tumour reducing in size.
Speaking of his son's illness, Tarmey told the newspaper: "There is no doubt that what happened had an influence on me deciding to leave the Street when I did."
He continued: "I felt I was better at home rather than at work. I felt I could do more."
Pub owner Carl, 44, is still receiving treatment for his condition and the Express reports that doctors have told him there is "every chance" he will live for at least another five years. His wife Sandra, father Bill and other family members are now working to raise funds and awareness for the Brain Tumour Research charity.
As part of the fundraising efforts, Bill will today visit Carl's pub in character as 'Ida Fag', a female alter ego used by Jack Duckworth in 2004 when he joined a women's bowling team. The actor is also auctioning off locks of his own hair online.
Bill said: "I will be making a prat of myself, but that's all right. We want more awareness of the illness and the dangers of brain tumours. If wearing a blonde wig and having my hair cut is the price I have to pay to have my son still with me, then that's no price at all."