What is the average compensation for on the job injury in TN, read below? ?

A friend has an attorney but is just wondering what it may be worth to be sure the lawyer is asking for a good amount. Friend fall on ice all in parking lot and breaks patella, minuscule tears ( not sure if that's right spell check corrected it) happened first of Jan. Work told them to return to avoid being fired and made doctors appt for 2 months away. After all this time of therapy they have decided on surgery with an expected four month recovery set to be done in June. Has been put on light duty and removed from mandatory overtime pay check went from 1000 a week to 400 a week and will get workers comp based on 400 while off for surgery. Lost their home due to not being able to pay bills, rent to own. Also has a family of five so it's major! Had to have someone drive them to and from work while injured with no gas mileage. Lawyer is supposed to be one of the best but won't give estimate just yet so the family is worried asking this question for them straight from my iPhone. The doc has said surgery may not fix everything and no matter what he does that they will still be looking at lifelong problems since there was some ore existing arthritis which will now be much worse. What do you estimate this to be worth? It's with a major automotive company and no union involved. Thanks