If I had kids, had pot candy, and lived in CO, I'd have a small lockbox/safe in the top of my closet with the candies in there... and/or simply have other forms of edibles that were less attractive to kids.
I find the story highly unlikely. It's probably more likely that he saw a weed cookie on the kitchen counter and ate it without knowing.
There are a lot of grandchildren that die after visiting their grandparents and taking an overdose of strong meds. Older people without children tend to forget that meds need to be locked up and don't want the inconvenience of locking meds away when they only have children around occasionally.
These are preventable deaths, they do happen, they happen way too often, but these are not reasons to make the meds / drugs illegal.
People like to throw out the "hospitalized" statement all the time. Just because someone was taken to the hospital does not mean that they were ever in any actual danger. Someone's kid eats an edible and "feels funny" so they are taken to the hospital. Someone's kid eats a bottle full of Vicodin that they thought were candy and are taken to the hospital.. if you think those two things present the same danger to the child than I don't even know how to respond.
These conversations are really fucking tedious because every single time I forget to say "I am strongly in favour of legalising drugs" someone leaps in to make some ridiculous point - here "no possible harm to children from cannabis".
If you think it's okay to let children take cannabis then I don't even know how to respond.
Grandparent sounds like they might not be a drinker. Fair enough, I have no issue with that, but - as you point out - there is a whole world between being teetotal and being drunk. The stereotype (which, yes, also goes for weed) is that one swig of a drink turns you into a staggering, vomiting wreck. In actuality, the mast majority of drinking (that I have experience of, anyway) is in moderation, with a meal, and results in a pleasant relaxed feeling which is totally unlike being drunk.
Weed, actually, is different - again, IME - in that the effects aren't quite so wide-ranging. Now, I've not experimented with really strong strains/forms, nor smoked an insane amount in one sitting, but a small amount has a very pleasant effect, and - for me - a greater amount doesn't really change it that much. I prefer to smoke in moderation, have a great time, and spend as little as possible.
I have never done anything I've regretted under the influence of marijuana, nor have I injured myself, embarrassed myself in public, or woken up the next day feeling even slightly bad, let alone like I want to stay in bed for a week. Apart from the legal status (here in the UK), MJ is a far superior drug in every way.
My personal opinion is that to prevent party-related mishaps later in life--particularly between the ages of 18 and 22--you need to teach your kids how to party responsibly before they leave your household. Thanks to the keen foresight of federal highway funding bills, this means you will almost invariably have to break the law in order to protect your kids in the US.
An ounce of prevention is worth a pound of not having to visit the cop shop or emergency department--or both--because your kid never learned about the potential dangers of satyrs and maenads before running off and joining the bacchanalia.