My boss died unexpectedly and business was immediately dissolved. I won't receive a W-2. Do I still need to wait to file Form 4852?

I worked at a small office for the last 7+ years. It was just my employer & I, so he handled payroll and business needs himself.

Towards the end of last year, my boss died unexpectedly. The business closed immediately and our clients were distributed elsewhere by a state professional association. His office was packed into a storage unit by the building's owners in case an heir appears. I definitely won't be receiving a W-2 this year.

I know I'll need to file a Form 4852, but most info I can find requires me to wait until the end of February and reach out to the IRS for assistance first. Since there's no business left to contact in this case, can I go ahead and file using the 4852 (& my last paystub), or do I still need to wait until late in the season to call the IRS and start my paperwork?