I also thought Sharon's lack of reaction (except to express concern for Kat) was odd given her fiancee Tom was burnt to death in a fire at the very same house 12 years ago.

Not every character can be in every episode.

That said, there was a fire at my parents house about 20 years ago which started in my bedroom (electrical fault, nothing suspicious) and I lost practically everything I owned including childhood moments and I don't dissolve into a puddle everytime I see a burnt out house, smell fire or smoke etc.

Tamwar does make the most sense to be affected as he was inside, suffered burns and still bears the scars both physical and emotional. I can say from experience that losing possessions is devastating but it pales when you consider the possibility of somebody having died or being badly injured. Maybe that is Patrick and Denise's attitude - the lost stuff but Yusef lost his life and Tamwar effectively lost his wife due to the trauma and was badly hurt.