I want my brother to be able to go camping, but he needs to cool Medicaments. Power should be available, can anybody help?

Hey Guys, so:

I have a little brother, right now he is 12 years old. We are both part of the local scout group, and this summer, my brother will go to a 2-week camp. Now, here's the problem:

He has to take daily doses of a medicament that has to be kept at 2-8°C (35.6-46.4°F). It is not much, a case not bigger than a shoe. But normally, there is no fridge in the camp, groceries etc. are bought fresh. Normal minibars and cooling cases from the internet we tried don't reach under 12°C (53.6°F).

We are aware that we can try to get a restaurant etc. to store it for us. But this solution is highly dependant on things we can't control, so I strongly dislike it. What I can say for sure is that we will have power available.

We are not stingy about thinks concerning that matter, so feel free to tell me everything that comes to your minds. I would also say that we can tolerate small temperature fluctuations, since we can stuff whatever is used as container with cooling packs.

It can also be big, we can transport it to the camp site with a car at the beginning and go take it back at the end.

So, tldr:

• Meds have to be kept at 2-8°C = 35,6-46,4°F
• Case is 18x9x4 [cm] = 7,1x3,5x1,6 [inches]
• Power is available
• Costs are not the first priority
• Asking other people to cool it has already been acknowledged

I am very grateful for all help I get, and appreciate every try. Just tell me what comes to your minds!