First, get a lawyer. For starters, if the company is conducting illegal activities, then you, as an owner, and as an owner who doesn't report the illegal activities, can be held accountable for them. Second, if you wish to save your interest in the business, you will need to determine your rights under the corporation type you have formed. Hopefully, you kept diligent records of the corporation/LLC/partnership. Third, if you want to buy them out, it's going to be tough without a Buy-Sell agreement. Depending on the type of corporation and state in which you are incorporated, there may be means of creating a buy-sell agreement without their consent. If this is possible, then you can make them an offer to buy out their shares, or require them to come up with the money to buy yours.
I think many attorneys will give you a free consultation. If your business is valuable, then it's worth at least entertaining the free advice. If it is not valuable and hence not worth the expense, get your name out of the corporation asap ... no need going to jail for their dirty deeds.
More information is needed.
A felony charge is just that: your friend was arrested for a felony, a major law violation.
His explanation that it "is a accusation" is baseless. He was arrested and accused of a crime, not just accused.
If he had to have a lawyer represent him, he was advised to do so by the court.
Felonies generally are punishable by jail terms of greater than one year.
Get the whole story and post it back as an amendment or edit to your question.