unvaxed kid visiting baby in hopsital??

So my sister in law has a 3 year old that wasn't vaccinated at birth or to my understanding throughout his entire first year I believe? she even went out of her way to falsify my daughters vaccine record for her own child (which) at the time I didnt know about, now I'm pregnant with baby #3 and idk if shes planning on going to visit us when I have this baby, with our other two kids she kind of stayed away and didnt visit because of a comment my husband had made to his mother regarding his brothers and sister about being unsanitary (somewhere along the lines of "tell them to shower before they come") at first I was like that's a little mean, but deep inside I was actually kind of glad he mentioned it, at the time only my mother in law came with one brother in law and my SIL never showed up. My concern now is should I let her and her son around my newborn? surprisingly my 18 month old son doesn't even let her touch or hold him its like if he didnt know them at all, every time they want to hold him he screams and even acts as if he doesn't want to touch them ( they are not the cleanest people and hardly visit) honestly since shes ani vax I wouldn't even know if she has her vaccines up to date??? Idk if I should be worried or I'm just parranoid? how long should I wait for her so to meet my baby?? or be around her? I've heard to wait until shes fully vaccinated but wouldn't that be until shes 1?? sorry I'm not to informed on the entire vaccines ir no vaccines since I have vaccinated both my children and pray to God that nothing happens to them! thank if you take time to read and answer ahead of time!!