I think the bounty/reputation should be preserved for the answers even after the question is deleted.

There are specific conditions in which rep on deleted posts are preserved:

First, if you’ve contributed something worthwhile to the site, you should keep the reputation for that even if it eventually gets deleted. “Worthwhile” here is defined as,

• A score of 3 or greater
• Visible on the site for at least 60 days

It is kind of not fair sometimes.

Well, nothing's fair in this world.

I think the bounty/reputation should be preserved for the answers even after the question is deleted.

There are specific conditions in which rep on deleted posts are preserved:

First, if you’ve contributed something worthwhile to the site, you should keep the reputation for that even if it eventually gets deleted. “Worthwhile” here is defined as,

• A score of 3 or greater
• Visible on the site for at least 60 days

It is kind of not fair sometimes.

Well, nothing's fair in this world.