Could you help explain the usage of 'as' in these two sentences?

1、The parents looked upon their children as their pride and joy.

2、People looked upon the situation as critical.

In sentence one, 'as' is a preposition since it's followed by nouns. Am I correct? But why is 'as' followed by an adjective in the second sentence?

Thank you.

Could you help explain the usage of 'as' in these two sentences?

1. The parents looked upon their children as their pride and joy.

2. People looked upon the situation as critical.

In sentence one, 'as' is a preposition since it's followed by nouns. Am I correct? Why is 'as' followed by an adjective in the second sentence?