What would be the cause of 2 five months kittens to not eat?

Kittens that young could be facing many problems that could trigger that. You were right to suggest the change in food along with a vet visit. Preferably she should just take the kitten in and have it checked out- it may have feline distemper *which is the equivalent to parvo in dogs* or something else could be going down.

EDIT: Agreed with josie I- If your friend does go to the vet then make sure they don't give the cat a lot of shots at one time. Do it 2 at a time at the most, you don't want to overwork that tiny immune system. Also, whenever it does get shots make sure the cat is healthy otherwise that could compromise the immune system as well.

It could be various things, they may not like the food or be bored of it, it may be too advanced for them, (certain adult formulas are too hefty for kittens) or they may be ill. Both trying other brands of food and a vets visit are worth doing. However if they have never eaten it may be that they are not completely weaned and have not learned to eat solids. However at 5 months they certainly should be. Do try the vets though as kittens lose strength very quickly.

They gotta be eating a little something, otherwise theyd die by now, but, maybe if you change the food if dry to wet cat food, they love this, but the poop is very messy nasty smelly, so I prefer giving them dry food, but this tires them sometimes, so I put a little bit of water in the dry food, and let it soak it up, they seem to like it better.

If this dont work, then maybe they have some worms, or parasites? who knows a vet would tell. But tell your friend to be ready with lots of money to go see the vet, cuz sometimes they make up stuff like "they have to be vaccinated" did you get them the feline leukemia vaccine?" "did you get em this" did you get them that".."you should this, you should that".

A bit more detail would be helpful. Have they stopped eating the foods they have previously eaten? If so, was it only one can/bag, or all foods that they had eaten before? Sometimes, a can or bag can be spoiled, and they can detect that and not eat it. Or, if the food was suddenly changed on them, they may not agree and if so, will refuse to eat.

But if it was the same food they have always eaten, and no new can or bag, then suspect a medical issue.

Squiggly, that turned me on SO much