4 days ago my wife had an emergency root canal due to an abscess. now on antibiotics, is there anything else that she can do to speed healing?

Time will heal: If the root canal was completed and the tooth sealed well it will heal in time. As long as the abscess does not convert to a cellulitis and your wife gets a fever it should improve significantly within 5-7 days. Once the tooth feels better make sure that a crown is placed on it if it does not have one. Monitor her condition closely for the next few days.

Yes and No: It's hard to advise without the specifics. Is the abscess still present? Is she still symptomatic? It is normal to feel a little sore (usually a day or two) but the soreness can last as long as one week. Take all the medication your dentist prescribed. If you have worse pain than before you need to go back to your dentist. Sometime you need incision and drainage or decompression performed.

NO: There is nothing you can do. In emergency cases with abscess, most of the times it is not recommended to finish the root canal because of many reasons. Probably the root canal is not finished yet. Antibiotics does not kill any microorganism inside the root canal. It only prevents the spread of the infection from the tooth to the rest of the body. Sometimes rinsing with salted warm water may help.