I am so sorry about your Uncle Wave's. You are right when it reminds us of our own parents. mortality. My parents are gone now, and mom's younger siblings area my agea and dh. THe Uncle dh age had open heart surgury last week. He is doing well. but Mom and two of her brothers are gone, Dad is gone and one brother advanced age.
My dh siblings are very muck older then he is. The sisters are still with us, he brothers are passed 15 and more years ago.
But for your dad's meds, there are a lot of medial type cooler, and we never had an issues with baby formula traveling.
Hugs for you, safe travels.
do