However, he has not been seen or heard in public since his return on February 24, fueling speculation that he is incapable of carrying out his job.
His silence has led to many Nigerian newspapers to continue reporting that Yar Adua is on a life support machine or in a coma.
There is also speculation that the president’s aides and first family are holding him hostage in the presidential villa until they can figure out how to retain influence and power in the event of his death.
Al Jazeera's Yvonne Ndege went to Katsina state in northern Nigeria, the president's home town, where she was able to track down one of the few members of Yar'Adua's family who would discuss the state of the president's health.
Zubaru Ali was given permission to meet with the ailing president because he is his first cousin and family spokesperson.
State of health
He said the president was able to walk, talk and eat, that he was asking after his relatives and thanking them for their prayers.
Yar'Adua left Nigeria on November 23 to receive treatment for pericarditis, an inflammation of the membrane surrounding the heart that can restrict normal beating.
He is also known to suffer from a chronic kidney condition and has long been criticised for not being able to work more than five or six hours a day.
Aside from the near constitutional crisis, Yar'Adua's long absence had prompted street protests by thousands across the country, demanding his resignation.
It also threatened to paralyse the government until parliament installed Goodluck Jonathan, the vice president, as acting head of state on February 9.
Nigeria's constitution said the president must make a written declaration that he is on vacation or unable to carry out his duties before a transfer of power could take place.
Yar'Adua had not officially given his consent to the transfer of power, but parliament said it based its decision on an interview that he gave the British Broadcasting Corporation (BBC) last month, saying that he would return to work once his doctors gave him the go-ahead.
Yar'Adua's absence has caused a ceasefire with fighters in the oil-rich Niger Delta to unravel and had left no one formally in charge of the nation of 150 million.
Source: Al Jazeera