Unfortunately - you may not deduct funeral expenses on your tax return.
The only place funeral expenses may be deducted estate tax return - form 706 schedule J - http://www.irs.gov/pub/irs-pdf/f706.pdf - but because your step-father's estate was insolvent - you likely was not required to file that return and do not owe any estate tax.
As an executor of his estate - you are responsible to file all tax returns for the decedent.
All these expenses are not deductible on decedent's income tax return. that is filled on the form 1040 - http://www.irs.gov/pub/irs-pdf/f1040.pdf
You may be also required to file an estate income tax return on the form 1041 - http://www.irs.gov/pub/irs-pdf/f1041.pdf
Estate tax return would be required if the value of the estate is above $2,000,000 - form 706 - http://www.irs.gov/pub/irs-pdf/f706.pdf - this return is used to calculate estate taxes. Funeral and legal expenses may be deducted here and would reduce estate taxes - - but because your step-father's estate was insolvent - you likely was not required to file that return and do not owe any estate tax.
You may not deduct funeral expenses for income tax purposes - these expenses are deductible for estate tax purposes only.