Who is Robert Greenstein from One True Thing and what is their importance?

Robert Greenstein is the lawyer Jeff hires to take Ellen's case in the murder trial. Robert Greenstein is described as a relatively unattractive man who drives a fancy sports car and had been recently abandoned by his wife. For all his personal shortcomings, Robert is a great lawyer for Ellen and she feels very comfortable around him. Robert is the only person not to treat Ellen with patronizing sympathy following her mother's death. He asks her direct questions and expects direct answers in return, which Ellen finds profoundly comforting.