Unless the new company is using trade secrets from the old company the new company is not liable for anything you did prior to starting the new corporation. Your shares may be subject to attachment if he gets a judgment against you.
The response given is not intended to create, nor does it create an ongoing duty to respond to questions. The response does not form an attorney-client relationship, nor is it intended to be anything other than the educated opinion of the author. It should not be relied upon as legal advice. The response given is based upon the limited facts provided by the person asking the question. To the extent additional or different facts exist, the response might possibly change.
Your brother is able to sue you personally, and also your new corporation, depending on the claim. He can also allege "alter ego" liability against your corporation, by claiming that your corporation isn't adhering to the requisite corporate formalities and you're blurring the distinction between the corporation and your personal identity.
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.
The new company might provide protection against itself and other shareholders, but if your brother obtains a judgment against you personally, your ownership in the new corporation could be used to satisfy the judgment.
If you would like to discuss any issues further, please feel free to contact my office. The link to my contact information is below. Thank you.
The foregoing is general information only, not specific legal advice. No attorney/client relation has been created or should be implied.