If you have filed your own tax return for 2014, you have no further responsibility with respect to tax filings for 2014.
I agree that you should send any tax information that you have related to your deceased husband to the Executor of your husband's estate.
Now, the only thing I will mention, is that if the estate has insufficient assets to satisfy your husbands tax liability, to the extent that you shared in his income for 2014, the IRS does have the ability to seek payment from the assets that resulted from the decedent's income.
Given what you have described, that appears to be highly unlikely.
One issue that is somewhat out of the ordinary is that usually the Surviving Spouse files a joint return with the decedent for the year of death. That would normally result in substantially less total income tax for decedent and not require any additional payments from the Surviving Spouse.
What filing status did you use on your income tax return for 2014?
Finally, did you file a joint return with your husband for 2013, or did you file using the Married Filing Separately filing status for 2013?