It appears that your father was ordered removed in absentia due to his failure to appear. In such a case he is subject not only the typical 10 year period of inadmissibility but to separate a 5 year period of inadmissibility due to the absentia order. Both periods would begin to run from the date of his departure from the U.S. However, the 5 year period can only waived upon a showing that his failure to appear was "reasonable."
More facts are needed to fully evaluate this case. The fact that you are a U.S. citizen (presumably over 21 years of age) is a good start. Consult with an experienced immigration attorney who can review the case and recommend how best to proceed to reunite you with your father.
You should consult with an immigration attorney. Where is your father? Does he have a USC or LPR parent or spouse if he is not in the United States? If he left, he is more than likely subject to a 10 year bar. Again, not knowing the specific facts of his case, it is hard to determine how he can adjust. You as a USC can petition for him and he is an immediate relative. However, the question is how can he get his green card. Consult with an experienced immgiration attorney. Good luck.
Mr. Lorenzon's answer to your question does not establish an attorney client relationship, but rather is meant to share knowledge with the general public. For specific advise on your case, you need to consult one on one with an immigration attorney. Mr. Lorenzon can be reached at 216 573 7322 or at firstname.lastname@example.org. All initial constulations are free.
If your father failed to appear for a hearing, then he's likely been removed in his absence. That's a bigger issue that needs resolution before you deal with others. Please retain counsel, obtain your father's court file and work with your attorney to make determinations on whether or not there is an in absentia order and what other bars may be in place.