BIL completely anti-vax, and hesitant to get newborn his vaccines -- advice?

Hi, sorry, this doesn't really typically fit this sub, but maybe some people may be able to give some advice here. (Please feel free to delete if unfitting)

My BIL is entirely anti-vax, he believes the covid vaccine was rushed, unsafe and that Pfizer came out and admitted they got it wrong(?). I don't really care about his own personal choices, but I find it concerning that he is hestitant to get his baby vaccinated.

He claims to have seen videos where after vaccination, the babies have "changed". He's even hesitant to give Gripe water for colic. He is extremely overprotective. I know it isn't my place, but I worry for my nephew, I don't really know how to navigate this.

My younger sister is a medical student, and has advised and educated him on vaccines, especially for young babies. My mother has a degree in health sciences and did the same. His own sister is a pharmacist and advises him regularly. But his family is generally anti-vax.

Thankfully, my sister (the babies mother) is not convinced by his arguments and is in favour of vaccinating her baby.

He placated himself (somewhat) that it's 'American' vaccines that are the issue, and he doesn't support American pharmaceutical companies. But what if the 6-in-1 vaccine is supplied by an American company, will he decline the vaccine?

I'm not really sure what I'm looking for here, perhaps I'm completely overstepping on his parenting, but maybe someone who has been in a similar position could advise?