Rev. Jackson also told the AP that his son was currently being evaluated and, depending on the results of the evaluation, could stay for an extended period of time.

On Monday, two of Jackson Jr.'s colleagues in the Illinois congressional delegation, Reps. Danny Davis and Bobby Rush, both Democrats, visited Jackson Jr. in his home. At the time, Rush said the congressman "looks well, but he doesn't feel as well as he looks." 

In June, Jackson Jr. took a leave from Congress citing exhaustion. Months later, Jackson Jr.'s office revealed that he was suffering from bipolar disorder.

Despite ensuing speculation that he could step down from his seat, the Illinois Democrat has continued to run for reelection. A WeAskAmerica survey released Monday found him leading Republican challenger Brian Woodworth 58 percent to 27 percent.