A person familiar with the matters in question may make an affidavit on behalf of another, but that person’s authority to make the affidavit must be clear. An attorney can make an affidavit for a client if the client is unable to make the affidavit. However, an attorney’s affidavit must still be based upon personal knowledge. The professional statements of a litigant’s attorney are treated as affidavits, and the attorney making a statement may be cross-examined regarding substance of the statement.
Moreover, a court will not accept some types of motions unless accompanied by an independent sworn statement or other evidence, in support of the need for the motion. In such a case, a court will accept an affidavit from the filing attorney in support of the motion rather than a sworn statement. A false swearing by a lawyer, could be grounds for severe penalty up to and including disbarment.