It sounds like she left the oil change too long and also did not top it up when required. In oher words, forgetfulness or neglect; you decide. It sounds like the valve lifters may have experienced excessive wear; how bad, I don’t know.
This vehicle should be checked out by a knowlegeable mechanic to get to know the true condition. It may need a cleanout with Seafoam to get all the crud out of the oil galleries.