Morphine in tablet form doesn't break up very well these days. Most pharmies are made with a special coating (you can remove it, but I'm not going to post how) that's for anti-abuse. Morphine has a coating but doesn't have anything added to it that would make snorting/crushing/banging it impossible (opana's however do). But, it takes like 10 seconds googling a "how to remove" and you'll get a tutorial video. I'm sure she knew how to do many of these things.
But morphine is kinda waxy when you break it down, not a fine powder - and it's rate for absorption (bioavailability) is significantly less via oral than it is insufflation. It would take quite a bit of morphine IR in food, drink - to knock a man down that size, because of the bioavailability). Now, say her husband was given fentanyl spray (it's nasal) - one spray could kill him if he had no tolerance. Same spray could be used under the tongue or simply on the palms of someone's hands. I'm way off on a tangent here but .. it is possible she snuck something in his food.. it would just have to be a lot if it was morphine, if the morphine was in tablet form. (because of how it breaks down)
I wonder if he caught her putting meds in his food before? I know that sounds crazy but maybe she couldn't get him to take his anxiety meds etc and thought by sneaking them in his food she could keep him on them?
BTW: I'm guessing he was most likely on a benzo, ativan tastes sweet but xanax tastes AWFUL. They purposely made xanax (and now ambien) taste bitter because of date rapes. Something I learned in class. Morphine has zero taste to it. Something I learned from using.