You friend need to consult with an immigration attorney.
NYC EXPERIENCED IMMIGRATION ATTORNEYS www.myattorneyusa.com; email: email@example.com; Phone: (866) 456-8654; Fax: 212-964-0440; Cell: 212-202-0325. The information contained in this answer is provided for informational purposes only, and should not be construed as legal advice on any subject matter.
For E2, you need to bring a lot of money to invest in the business, and for O-1 you should have high level of achievements in the related field (you can read more about it here: https://www.fattahi-law.com/immigration/o-1-visa/). However, details should be discussed with an immigration attorney, since the information you provided is not sufficient, and both of these categories (as well as and any other visa category that you could potentially be eligible for) need extensive legal discussions for eligibility determination.
Your friend needs to speak with and retain an attorney if they are serious about this. Just because they start a business does not mean you would qualify for a visa through them, there are many more requirements.
Legal disclaimer: The statement above is general in nature, as not all the facts are known. You should retain an attorney to review all the facts specific to your case in order to receive advise specific to your case. The statement above does not create an attorney/client relationship.