Hold Pushbutton for soft latch after X seconds
This can be done the old way by charging and discharging a cap into a comparator.  However, it only takes two parts to do this with current technology.  That will take less board space, is more flexible when the inevitable changes are required, more accurate, and about the same cost.

Use something like a PIC 10F200.  That's a tiny microcontroller that comes in a SOT-23 package.  That's the same package used by small discrete transistors.  It costs about $.25 in quantity.

Connect the button between one of the inputs and ground.  Enable the internal pullup on that input.  In firmware, whenever the input is high (button released), reset a timer to your 5 second delay time.  Whenever the input is low (button pressed), count down.  When the timer gets to 0, assert the output.

The reason I say this solution is two parts instead of just one is because there should be a bypass cap across Vdd to Vss of the micro.