Lauda was up and around quite quickly and back in the car within 6 weeks. Robert will, depending on how bad the nerve damage was, have to relearn how to use his hand. It's not a relevant comparison. Neither is Massa though - that was a head injury.
Quite apart from that, he has not done any training apart from physiotherapthy for nearly a year and much of that time has been spent in hospital. It will take months to get back into good enough shape to do serious F1 driving, by which time he could be nearly 2 years out of the car. I think he only did one test on Pirelli and the tyres have evolved a great deal since then.
He has a long way to go. I very much doubt he would walk into a Red Bull, McLaren or Ferrari straight away.