Try and persuade him.

You've always been great at persuasion and often used it when stuck in a bad situation, so you try and use your expert skills to persuade him,

"You're no fun nowadays, you never do anything fun, when was the last time we hung out together as buddies? this is the first time in a while I've spoken to you and asked if you wanna hang out. Plus as an upside its caving, we could be exploring a cave no one has ever seen yet, it could have gems in, like quartz, you enjoy that stuff, right?"

You know just how much he likes shiny stuff, especially shiny rocks and gems like quartz, sapphire and emeralds and just how gullible he is about it. Trying to grab his attention by using something he desires is perfect! It's valuable and he loves it because it has sparkle to it.

"That is very tempting, but if you're really this **** to go, you should just go by yourself... I'll try and make it there if I have and spare time, but I can't promise I will be there."

You pack up and head out to the cave and wait for him at the entrance, it's only a small walk away from where you live so by the time your friend gets there in his car you should be there, same time but you made it on foot. You wait for 5 minutes, that turns into 10, then 15, then half an hour... then a whole hour has passed by and no sign of your friend. Only thin trees covered in moss that look so fragile you could probably kick the things down, maybe punch it down too if you could bare a bit of pain. A few bugs that are maybe no smaller than your ring finger, some fast, some slow. The occasional tweeting of a magpie and what other birds are flying above. A few frogs or rabbits would pass by at your feet quickly but apart from them things, no sign of your friend.