Sorry to hear poor Alfie is having a few problems at the moment, and also sorry on the loss of your old dog, it sounds like Alfie used your old dog as his confidence booster and is now missing him too, Alfie needs to get over his grieving period and I think going to socialising class is a good move also trying to carry on with a normal routine without overly fussing him, ressure him when he is a good boy and such like ... which I'm sure you do anyway!.....
Hopefully in time you will be able to return some of his confidence and I know COL members will give you some good advice......