A non attorney may prepare and file these forms on someone else's behalf. However, make sure you complete part where it asks who prepared it, and provide your contact information. There is no reporting requirement. You will be receiving Notice of Action letters from USCIS, since you will be considered a representative of the case, and in fact, responsible for it.
Contact immigration attorney Gintare Grigaite at 646-407-2331. Answers on AVVO do not constitute legal advice and do not form attorney-client relationship. Always consult an attorney for a legal advice.
A non-attorney can prepare documents so long as they report it on the form.
It is unclear from your posting whether you initially believed the filer was a lawyer. This is considered unauthorized practice of law and is a national concern [http://www.stopnotariofraud.org/]. There should be ways in there to get help if that is the case.