IRS is likely to waive the late filing penalty but keep the late paying penalty. But it does not hurt to ask for all penalties to be forgiven. Taxpayer(s) needs to sign the request.

I would NOT send the money on the penalty - I have always felt that IRS was less likely to waive if they had the money in their hands. But have taxpayer pay the tax (labeled as "paying the tax 1st").

Details like the obit help.