Advice?

Ok so basically my dad and his girlfriend are addicted to meth. They have a 3 month old baby who I just met for the first time yesterday. There were a couple of red flags to say the least, such as my dad forgetting to strap her into her car seat when he put her in the back seat of her mom’s car. They also put her in the side seat not the middle seat, not the biggest deal I guess but still didn’t sit well with me. It was cold out last night but he had the blanket covering her face it was stressing me out. Also she is so tiny like sooo tiny. I’m not sure if the mom stopped using drugs while pregnant or not. But I don’t know what I can do about it? Yesterday was my first time seeing my dad in 2 years, him and his gf rent an apartment right across the border in Mexico (I live in San Diego). I don’t know when I will see my sister again. I know the mom has someone in mexico take care of the baby a lot but they don’t seem like the best people. I would literally adopt her tomorrow if they asked. When the mom came to pick her up I told her she could bring her to my house whenever she needed and that I would gladly take care of her for however long. But I am seriously so worried !!