Having a toddler with you in long drives can really be nerve rattling. Here are some tricks I use with my toddler: -Play music and sing with your little one. Add some hand dances too. -Prepare snacks. It keeps the child busy and avoids tantrums from getting hungry too. -Set aside toys that are only to be played with in the car. It makes them have a reason to get excited about the car ride. But make sure that these are safe to play with inside the car. -Play games like Eye Spy, Count the cars, Identify the colors of the things that you see -Give them books to read -Orient them first before getting inside the car on how to behave during the long drive. -Rely on the old "reward system".. Offer them a reward(one that you're willing to do or spend on) for doing as they are told in the car Hope we'll tame the fussy nephew with these tips :)
Here's something that might help: https://ph.theasianparent.com/stop-your-child-from-throwing-tantrums-before-they-even-start/ I also read before that tantrums are a result of children not being able to handle the enormity of what they're feeling. For example, a child throwing a fit at her sister's party may be explained by jealousy but the child doesn't know that word. Telling the child about the concept helps him grasp the situation and so calm down. It's also good to let a child get frustrated every now and then. If you always give a child what he wants, it's impossible to fulfill ALL his wishes and at some point you won't be able to and it's such a new situation that the child won't be able to handle it.