bringing my 15 week old puppy to visit parents with 4 year old littermates for 10 days, will they traumatize him and will their negative traits rub off on him?

A few days after my puppy gets his next round of shots, I am taking him to visit my parents for 10 days. They have 2 littermates that probably have littermate syndrome. One barks with other dogs out of fear and apparently they aren’t the best with puppies (no biting or anything just loud).

We’ll introduce separately outside of course, with the friendlier one starting first. They are similar sizes, and my dog will have a pen and crate so they won’t be able to get in their space.

I’m worried that this will forever taint his interactions with other dogs and confidence, and he will come back a different dog. He is so sweet and such a good boy I don’t want this to ruin him in any way. If anyone has advice, I would love to hear.