The minister said Buhari refused to use taxpayers' money because of his moral uprightness.
The president spent a combined 154 days in London on two separate medical visits to treat the undisclosed illness, prompting criticism about the taxpayers' money being wasted in medical costs in the foreign country.
While speaking to a crowd recently in a video published by President Buhari's Personal Assistant on Social Media, Lauretta Onochie, on Monday, April 30, 2018, Usani claimed the president did not pay for his treatment with taxpayers' money even though it's his right.
According to the minister, the president refused to use taxpayers' money because of his moral uprightness.
He said, "President Buhari is such a simple man that even when he does unofficial responsibilities, for fear of misrepresentation of his actions, he would rather sacrifice and urge his friends and well-wishers to sponsor certain things that concern him.
"For instance, you heard about the time he went on medical treatment: no government 10 kobo was used to fund that medical treatment.
"If they had done that, by now, you would have been hearing on social media how many billions were used for his health.
"We know it's a right that he should have enjoyed, but the moral rectitude is what will not allow him do that because he lives by example."
Usani further compared Buhari's administration to those of former presidents, Olusegun Obasanjo and Goodluck Jonathan, and rated it to be more successful.