Family with lice

So my daughter is 4 and she was a cousin that lives nearby that is just a few months younger. My Bil and his wife always want us to come over to let the girls play but we haven't been going over as much recently because of an outbreak of lice they say they don't have. I am very careful about checking my daughters hair after she plays with other kids because we all got lice after she stayed the night with her cousin one night. It was aweful so I would rather be safe than sorry than have us all get it again. After that my SIL treated he daughters hair with things like baby oil and electric combs but I don't think she ever really got rid of the problem. Both her and Bil have bad eyes and they keep coming back. We still go over every now and then because they love playing with each other and I just do lice checks after we get home. I have found just one or two on occasion and get them out. It's not to hard because my kid has light blond hair so it's easy to see through and goes through the comb well but it's so annoying. Last week I told my BIL I think she still had lice because when they were over I saw nits and a live bug or two on her and he went home and told SIL and said he didn't see anything when he looked in her hair with a flashlight. I don't know what to do besides to go over with a lice comb and show them but that feels a bit rude to me. My SIL is already mad that I told her husband I think her kid has lice but I'm tired of the endless lice circle. I feel so bad for my neice having to live with lice because they won't admit there is a problem. I feel like I'm crazy but I have seen them in her hair. Do I just stop going over, or try to show them there are still bugs in her hair. Our kids love playing together but I hate living in fear and doing all the hair checks. via /r/Parenting http://ift.tt/2mPWJHH