Manager creating unexpected goals while in notice period.

This is my first time serving notice period. The new project just started, initially we planned with 4 resources 4-6 months of work. 1 already left, 1 pen down a few weeks before me. Now he is expecting I'll finish the work in next 15-45 days. Domain I'm never worked, so everything is new. What are the chances that this might delay the last working day? Initially, I was supporting with as much as possible I'll help, now this is going beyond irritation.

Any help?