[Dayrion]

Uhm, you have to edit something. I did a mistake :
MAX_PLAYER » MAX_PLAYERS

PHP код:

new Float:afkHealth[MAX_PLAYERS] 
// AFK CMD | Get player health : 
GetPlayerHealth(playerid, afkHealth[playerid]); 

// Restore health 
SetPlayerHealth(playerid, afkHealth[playerid]);