If your mother made an offer through an agent then she most likely signed an Exclusive Buyer's Agency agreement with the buyer's agent that she made an offer through. If you had not wanted the services of an agent then an agreement should have been reached with the seller before an agent was procured by the seller.
Hope this helps,
However, if you are fortunate enough to have one working for you, they will help you negotiate an appropriate amount of funds from the seller in order to pay your closing costs.....unless you are just paying cash and are not concerned about protecting your rights or interests or money.
Otherwise, it's always best to interview a few and select one which whom you are comfortable working.
The home goes under contract
The process will be more smooth since both sides have their own representation.
Your lender should be able to give you a Good Faith Estimate of all the costs involved in acquiring a loan and closing costs associated with it. If you are paying cash, the closing costs will be less, but you will still have inspection costs, title search and insurance and attorney fees. Usually, I tell my buyers that closing costs are somewhere around 3% to 4% of the purchase price.
If you're not clear who is obligated to your mother, look at the contract. The fact that neither agent had anything to do with your knowing of the home is totally irrelevant. You would be better off with a buyers agent, then without, though if the buyers agent is also the listing agent then you've allowed Dual Agency which while perfectly legal here in NC; presents in my opnion a conflict of interest.
If the seller has agreed to compensate a buyer agent, then the commission offered is subtracted from the commission spelled out in the Buyer Agency Agreement between the agent's firm and your mother. That commission may or may not cover the entire agreement between these two indivisuals. If it does, great. But if not, the agent/firm may require the buyer to make up the shortage. If it is very close, some firm's will waive the difference. But if it is considerable... well let's just say this is a conversation that should have been discussed up front.
I would recommend that you have your agent at every inspection, ask for their guidance in negotiating repairs, make sure they are walking you through every step in the process from here forward. Believe me, the hard part just may be yet to come!
Best of luck!!