Yeah, there is no where in hell that he will be allowed to stay for 3 years if he keeps this level up, that goes without saying.
If his release clause is only 40m euros, then I dont mind signing him, even though he ideally should have been a couple of years older. Going from one extreme of signing Mathieus to another extreme of signing 18 year olds for 40m might not be the best solution, but we are in quite a mess and he looks like a perfect signing for our midfield with very good passing range and vision.