Ah, shit. So sad to read. Obviously never met yourself or Oz, but clearly a loved doggo. Said goodbye to the last of my 3 cats earlier this year, so know that while there will be sadness, it was a life well lived and he will have left a mass of good memories.

Generally a Pro-arte 0, but sometimes use pretty cheap 0 and 00 brushes you can buy in pack of 10 on amazon. Don't do lots of letting. And no secrets; little paint in a mute colour first - sketch out. Overpaint more carefully in main colour. Tidy edges with b/g or base colour.