Laravel model observer method doesn't get fired - laravel

Question

In my Laravel (7.x) I am trying to use Observers for updating device_inventories table if the value of the record if the record of the subscriber_devices table is updated as inactive.
device_inventories | subscriber_devices
----------------------- | --------------------------------
# | title | status | # | device_inventory_id | status
----------------------- | --------------------------------
1 | device-1 | active | 1 | 1 | active
2 | device-2 | active | 2 | 2 | active
For example:
Suppose I update the record id = 2 of subscriber_devices to status = inactive then the value of device_inventories / status should be updated to replacement. Assuming, that the device was damaged and needs to be sent for replacement.
AppServiceProvider.php
use App\SubscriberDevice;
use App\Observers\ObserverChangeDeviceInventoryStatusToReplacement;
class AppServiceProvider extends ServiceProvider
{
public function boot()
{
SubscriberDevice::observe(ObserverChangeDeviceInventoryStatusToReplacement::class);
}
}
App\Observers\ObserverChangeDeviceInventoryStatusToReplacement.php
use App\DeviceInventory;
use App\SubscriberDevice;
class ObserverChangeDeviceInventoryStatusToReplacement
{
public function updated(SubscriberDevice $SubscriberDevice)
{
DeviceInventory::where('id', $SubscriberDevice->device_inventory_id)->update([
'status' => 'replacement'
]);
}
}
App\SubscriberDevice.php
class SubscriberDevice extends Model
{
protected $table = 'subscriber_devices';
public function _status($token, $reason)
{
self::where('token', $token)->update([
'reason' => $reason,
'status' => 'inactive',
]);
}
}
The observer method doesn't seems to be firing. What am I doing wrong.?

Answer 1

Thanks to #EmptyBrain.
App\SubscriberDevice.php
class SubscriberDevice extends Model
{
protected $table = 'subscriber_devices';
public function _status($token, $reason)
{
$self = self::where('token', $token)->first();
$self->update([
'reason' => $reason,
'status' => 'inactive',
]);
}
}
Reference laravel Eloquent model update event is not fired