My cat keeps being sick ?

Abrupt diet changes can have an affect on an animal. It's not so much wither it's wet or dry food that keeps changing it's the actual brand or type of food that keeps getting changed. Talk to your neighboor so you both can feed the same brand or type of food. Iams for cats is a good brand or type of food. This is only if you suspect it's having different brands/types of food all the time. Always remember if you are concerned that your animal is not feeling right the Vet is the one to see. Good Luck!