[SilentSoul]

Very easy to do that you just need to use SetPlayerHealth
Btw , here is the codes

Strcmp

pawn Код:

public OnPlayerCommandText(playerid, cmdtext[])
{
    if (strcmp("/heal", cmdtext, true, 10) == 0)
    {
        SetPlayerHealth(playerid, 100.0);
        return 1;
    }
    return 0;
}

dcmd

pawn Код:

dcmd_heal(playerid, params[])
{
    SetPlayerHealth(playerid,100);
    return 1;
}

PS: sorry i didn't got you , when the player die he will automatically respawned , so could you explain please what are you trying to do ?