No judge of a probate court shall engage, directly or indirectly, in the practice of law in his own name or in the name of another, as open or silent partner, or otherwise:

(1) In any case or proceeding in his own court;

(2) In another court in a case or matter of which his own court has, has had, or may have jurisdiction; or

(3) In any court or any matter whatever, in behalf of or against any executor, administrator, guardian, trustee, or other person acting in a representative capacity whose duty it is to make returns to his court, except to give such advice or instructions as his duty may require of him as judge in his own court, for which he shall receive only such fees as are prescribed by law.