Late Mother Supposedly Owes A Large Amount Of Money To Irs

I recently got a letter in the mail addressed to my mother from the IRS and how she owes them a bunch of money because PayPal filed her many transactions where she was just borrowing/moving money/giving other people cash to transfer it to her as income.

She doesn't have the will and I haven't gone through probate, though according to PA law I shouldn't need to, or at most I'd need a small state affidavit. I asked over on r/tax but I'm still unsure if they're able to claim the amount of life insurance she left me to use for her preparations and if I should even contact her banks to get her savings out.