It’s not quite like when you have a lawyer in other venues, you can talk to the IRS but they are legal representatives, so you might want to consult with them about it. If you question their work though you can reach out directly to IRS. Optima should be sharing all their correspondence or paperwork with you.

$4000 is a pretty steep fee.

Since you’d dad is living paycheck to paycheck now, optima or you can probably get him into a “currently uncollectible” status, which means no payments are collected until things change, or you can get on a payment plan that is reasonable and manageable. Either of those can prevent a lien filed by irs, which is good for credit - keeps credit clean.

Check all optima’s work though for any errors, missed deductions or missed credits.

Self employed people do have heavy burdens, so the $20k isn’t necessarily surprising. They pay 100-percent of social security etc. That’s 15-percent right there, before the main deductible. It’s a whopper for the self employed. .

Oh, also, the IRS has a tax payer advocate’s office in every state. In the future if you have any problems, say, he can’t make a monthly pmt, or you need new help, they can open a case file for you. They are generally very very good and very helpful.