Hi Inpar. It's definitely not your or or colleagues responsibility for the success or demise of the company. You said the word boss, which in our English dictionary means boss meaning, definition, what is boss: the person who is in charge of an organization and who tells others what to do: .
The boss is responsible, you take instruction from them but, they cannot dump their responsibilities onto you!!! I know that's what bosses tend to do but really, she wants to stand up and be counted! She's one small cog who is trying to dump all her little cog teeth onto you and your colleague. Nah, do what you normally do and don't let her dump her inadequacies onto you, she's the boss, now it's time for her to sit at the grown ups table, and grow a pair!
Try not to stress yourself out, easier said than done, but don't take the weight on your shoulders!