There is no income tax paid on life insurance benefits, in most cases. Life insurance does not go through probate if the beneficiary of the life insurance policy is a person. If the estate is large enough, estate taxes must be paid on life insurance. So in that respect, the IRS can take life insurance money, through applicable taxes.
If you are asking if the IRS can take the proceeds of a life insurance policy if the insured person passes while owing back pay to the IRS, if the beneficiary is a person, the IRS cannot take the life insurance money from the beneficiary. An exception would be if the beneficiary filed jointly with the insured, or if the beneficiary owed his/her own money to the IRS.
If you are asking if the IRS can take the proceeds of a life insurance policy if the insured person passes while owing back pay to the IRS, if the beneficiary is a person, the IRS cannot take the life insurance money from the beneficiary. An exception would be if the beneficiary filed jointly with the insured, or if the beneficiary owed his/her own money to the IRS.