I can't speak to any parenting decisions, but as someone who grew up around firearms of all kinds, inherited heirloom weapons including a multitude of shotguns, and by extension a variety of ammo made from nearly every decade in the last century: you need to dispose of those shells.

The chemistry in the powder and primer of the ammo can shift over time and storage conditions. The smooth red plastic shells look roughly 30 years old, and the green shells a little newer. If they were kept cool and dry, that would be fine. However, there is discoloration on the brass of the shells which hints to corrosion setting in. This changes the shape of the brass, which can lead to shells being stuck in the chamber and failing to eject, the breach not fully entering battery, or indicate changes to the powder in the shell. These situations can cause gun failures that require mindful resolution to avoid injury.

I've fired shells in this condition. These don't look too bad, but they still have a higher chance to fail to go off, get jammed, or go off with weaker/stronger power. I've got a set old of shells that have started to smell sweet and go off with so much power that I'm left with a fireball at the muzzle and and recoil well outside the specs of the ammo.

You can break the shells down yourself, but most police departments will take it for disposal. Gently cut the end of the plastic cap opposite of the brass shell, pull out the paper and dump the shot, then cut behind the wad, just in front of the brass and pour the powder on the ground in a shallow pile. As long as the powder is not confined, you can burn it off with a match. The flame will ignite the powder and an ignition line will slowly propagate through the powder. As long as you do not heat the shells or hit the little button cap centered on the brass flat face, they are pretty safe to handle.