He said: "The motive was financial, relating to the fact that Mr Ali was indicating an intention to return to the Yemen with a view to marrying and remaining there.
In August 1998 Hassan Nasser, 44, cut his father's throat and then sealed the body in a purpose-built tomb in the basement of their home in Doncaster, South Yorkshire.
His son, Kassan Mohammed, 21, helped him and together they continued to claim the old man's pension.
The "body in the bag" was discovered by two men in January last year and so began a lengthy murder inquiry.
Police, using BBC's Crimewatch UK programme, eventually identified the dead man as Mohammed Nasser Ali, 75, a retired cutler and prominent member of Sheffield's Yemeni community.
'Violent and brutal'
Nasser and Mohammed's trial was told the men banked more than £9,000 by fraudulently claiming the victim's pension.
Passing sentence the judge, Mr Justice Maurice Kay, said the killing was as "violent and brutal" as was possible to imagine.
He said: "The motive was financial, relating to the fact that Mr Ali was indicating an intention to return to the Yemen with a view to marrying and remaining there.
"After you murdered Mr Ali you then embarked on an appalling process of concealment, dishonesty and fraud.
"You buried him in the cellar of the house in a purpose-built tomb where he remained for over two years.
"You only removed his body from there so as to facilitate a sale of the house. During that time you both helped yourselves to his continuing pension."
Mr Justice Kay accepted Kassan had not been involved in the actual killing but said he had been involved in its planning.
He told him: "I have not the slightest doubt you were the lesser party. During a period of time you fell under the malign influence of your father.
"You were 17 at the time - until these events you were making something of your life in a decent way. However, you too became involved in a most wicked crime."
Afterwards Detective Superintendent Bob Varey, who led the inquiry, said: "We always knew if we could identify the body we could find out what had happened.
"I was always confident the facial reconstruction would crack the case."