Our pet bunny/hare wouldnt eat anything all day.?

my sister and mom said that our bunny hasnt eaten all day. it has been very week and it is very hungry. it wouldnt eat any of his food. it will just drink water. what should i do? i cant see its teeth because it freaks out and my mom refuses to take it to the vet. i feel bad that its feeling this way and it might die. it has also been sneezing since it got here. help :(