Sorry for your loss. When you mail in an extension you do not receive a notice that the IRS received it. You receive an accepted notice when you e-file an extension. When you are due a refund or don't owe taxes there is no penalty for filing a late return. If taxes are owed, then they needed to be paid by April 15, 2019 to avoid any penalty and interest. If taxes are owed the penalty & interest accumulate until the taxes are paid in full.
