Guide me for my tooth treatment.

I m 19 male and had a half broken tooth The tooth is on the upper rear side i thino its called molar which helps in crushing food It was broken 2/3 yrs ago and i had a filling on it which got off my tooth unexpectedly Now my tooth started  feeling a heavy pain of sensitivity though my all other teeths were sensitive but this one came to be very painfull Now my sister in law is a dentist She diagnosed and with a help of drill and water jet removed the bacteria from my teeth She stated that the bacteria was just above but the nerve of the tooth but there is a thin skin above the nerve which had prevented the bacteria to get into the nerve so she took the bacteria out and filled it with temprory mixture and cotton She said if the skin above the nerve becomes thick then she will fill the teeth and put a cap Otherwise she will perform root canal So my ques are The treatment she is doing. Is that right Secondly she gave me options like have a root canal or you can have a tooth implant.