He wants to take care of these wild kittens but I told him that we can't.
Why can't you take care of them?
We'll have to spend money on food, litter, kitten shampoo etc. It's not cheap to take care of an animal
Maybe you can find a different home for them. I understand it costs a lot to take care of an animal.
I wish we could help them, but the financial restraints are too much.
It's kind that you want to help, but sometimes things are just too much and you have to set priorities. You shouldn't beat yourself up over this as it's out of your control.