Thank you, this is very helpful. I'm a little confused though... I figured if he pleas guilty he has a better chance of them reducing the charges?
If he just pleads guilty at his appearance, then the charge he was cited with is the charge that will stick, and the court will then decide how to sentence him on that charge (the prosecutor will make a suggestion on how to sentence as well). If you plea bargain, which is something initiated outside of the courtroom between attorneys, you essentially agree that your dad will plead guilty, but only to a lesser charge.
Because your dad sounds like he needs someone to help him, you should really seek an attorney to do so. You should be aware that even though you are a good a son, you are prohibited from appearing on his behalf in criminal court or making arguments for him - that is considered the unauthorized practice of law as you are not an attorney.
If you have any other questions, please ask. But please secure a criminal/traffic lawyer to advocate for your Dad.
His court date is this coming Friday. Should he hire a lawyer for the initial court appearance or do people normally plea not guilty and then bring the lawyer to the next court date?
There is no normal. But given that your dad appears to be confused at times, you will probably want someone to act for him in all ways. You should remember that once you get into the courtroom, this becomes about the State and your Dad - You will not get to stand up and inform the court that your Dad pleads not guilty, or advocate for him at the proceeding. If he's in the condition you suggest, you'll probably want to have an attorney there to take the reins.