Mr Appleby died in hospital in Milton Keynes on April 21 after contracting the illness.
His family say he had been fit and well before contracting coronavirus and said that his death has come as a shock.
His niece, Laura Bell, said: “I think more than anything it’s been a shock. He seemed to be getting better, then he wasn’t.
“I don’t thinks anyone knows how dangerous it is and another 20,000 families are going through this. He was really healthy and was still very active before he died.”
Mr Appleby spent two weeks in intensive care where, at times he seemed to be improving, but he eventually lost the fight.
Mr Appleby was highly regarded at the FA, which he retired from in 2015. He then joined the Spartan South Midlands League as a director in 2016. He was key to the successful restructuring of the National League System in 2004/05, and the creation of the National League North and South divisions.
He went on to oversee restructuring at Step 5 of the football pyramid and below. Step 5 includes the Northern League, which includes Ashington FC and Bedlington Terriers
Although he left Alnwick in 1978, he was a frequent visitor to his home town and was up last Christmas for a big family get-together. He was a huge fan of Alnwick Town, as well as following Newcastle United.
Mr Appleby was also an honorary Freeman of Alnwick.
He leaves behind his son Jamie and partner Trudy.
His niece, who lives in Northumberland, said of her Uncle: “He was football mad and he just had the driest sense of humour you’ve even heard. But he was really professional in his job. There were a lot of hard decisions he had to make, but he was always really respected. He tried his best for them all.
“He was just up at Christmas and met my new twins. He was close to my mam, Angela, his older sister.
“He was really well-known up here even after he moved away.”