I want to catch a stray but I don't want to separate it from it's parents

It's 3 cats,one being a baby in my neighborhood(the one I want to catch),only downside is I don't want to separate the parents and child wich I don't feel that great about doing.If the parents weren't there I wouldn't think twice the kitten is 6 weeks and probably at least 8 now.i have the means and money to take care of the Baby and even the parents.l but my mom said if Can't take the parents because they have fleas and she doesn't want to bring them inside.Right now were out of state so I have plenty of time to consider,I would also like suggestions for food and treats?I was going to go with meow mix but I heard some things,most likely I will probably not get the kitten out of guilt,I'm also not sure if this is the right tag but I want to at least try to get a better understanding of what to do. And if I cant do anything I at least want to know what I can do to help them stay safe because they're are dogs around