Burnley Football Club's goal-scoring legend continues to recover in hospital after having undergone an operation on his brain.
The former striker and fans' favourite, who played 126 times for Burnley FC between 1960 and 1968, suffered a fractured skull and broken bones when he fell down the stairs earlier this month at his home in Burnley.
His son, Jonathan, said: "My father has undergone surgery to his brain. The doctors had to remove pooled blood and relieve the pressure from his brain. Post-operatively he is doing well and as a family we are pleased with the results. It was an extremely difficult decision to go ahead with the procedure as its major surgery. The operation lasted over three hours and since then we have seen a significant improvement in dad's condition. He remains in good spirits, his appetite is returning and he is speech is getting better, but it's a long road to recovery."
He added: "We would like our dad to be discharged home, but we realise that the hospital is the best place for him to optimise his recovery. He's is making progress each and every day."
Jonathan went on to thank wellwishers, fans, friends, relatives and neighbours for their love and best wishes. "We are truly grateful for everyone's support."
He also paid tribute to his mum, Rita, who he said was the family's "rock". He stated: "Mum has been incredible and extremely brave. It's a worrying time for us as a family and extremely difficult as mum has had to travel every day and sit beside my dad for 10-12 hours each day. She's been amazing."
Jonathan concluded by expressing his gratitude to the nursing staff on Wards 2a and 2b at Royal Preston Hospital. He said: "They have been wonderful with my dad and all of the family."
Mr Irvine, a Northern Ireland international player, scored 78 goals for the Clarets and eight for his country in 23 appearances.
In 1965/66 he scored 29 goals and was the leading scorer in the old First Division.
After leaving Turf Moor he also played for Preston North End, Brighton and Hove Albion, and Halifax Town ending his career at Great Harwood before hanging up his boots aged 29 in 1974.