According to Spotrac:
While a full recovery is the only real focus here, in response to questions regarding Tua Tagovailoa's contract:
The deal includes $167M guaranteed for injury, $43M of which has been paid in 2024.
If he's medically cleared to return to football, but opts to retire, he will forego the remaining $124M guaranteed (barring a custom settlement).
If he's medically forced into retirement, he has a right to collect the $124M remaining.