My dad has a history of getting presents very very wrong. A few years ago I gave him the name of a perfume for my mums birthday. He presented her with a stew pot- he thought he was being practical 
It's my mums birthday coming up and it's a big one so I've been discussing presents with my dad. My mum had pointed out a skirt she wanted so I suggested that.
I got a phone call today saying my dad has seen a dress "for large ladies" that he thinks my mum would like for her birthday. My mum is a size 14. I then asked him to take a picture of it but that horrified him as people might think he's a pervert with some sort of women's dress fetish. So he eventually just bought the dress in a size 22. It looks like a tent.
I asked my sister to reason with him but he's so happy that he's got a thoughtful gift, all be it completely wrong. How on earth do I deal with this without my dad getting upset, even though he's got it wrong, his hearts in the right place, and my mum not being upset because she's got a rubbish present?