yup I have to agree that the chi is not one of the breeds considered hypo allergenic. Many curly coated breeds as well as single coated breeds tend to be better for those with allergies.
If you are looking at a small dog that may not bother your mother I agree the poodle is a good choice. Others would be the:
maltese
bichon
chinese crested
american hairless terrier
schnauzer
bolognese
coton de tulear
I think there are a couple others but this is what I can think of off the top of my head. There are also some mid to larger sized dogs too. But if your chi doesn't bother your mother, she may be able to get away with getting one of those.