I need to prevent adult DS2, who has autism, learning disabilities and many food intolerances, from opening the freezer, which is the bottom half of a built-in fridge-freezer. Looking on Amazon there are lots of possibilities but they're all for babies or toddlers. DS2 is fairly strong but his fine motor skills aren't great. Any ideas? I'd rather avoid anything with a key if possible as I think it would just drive us mad. Or madder....