His Ibiza example was to accentuate his situation and how he's tried to deal with it and the absence of any solution evident to him. As is the more humble (and important) examples of being left by someone he loved and the boredoms he faces waiting for his regular joe friends to get off from work while he sits staring at a computer screen. The wealth he's accumulated has hit a singularity of usefulness in his own mind yet he still faces difficulties he possible feels ill-equipped, in experience and knowledge, to deal with. This is possibly (dangerous armchair hypothesis here) an adverse consequence of his rapid influx of wealth and over reliance on it as a solution to life issues, which for most people include bills, housing, food, and novelty entertainment goods/adventures.
Maybe he is an asshole. I don't fucking know, because I don't follow his twitter, I don't follow his business and economic adventures, and haven't expressed much interest in the lifestyle of Notch beyond various bullshit posted here and elsewhere about Minecraft's fortune, selling to Microsoft, and some house party pictures I saw a little back. That's a lie; I did see him in an interview once, and he seemed pretty quiet and grounded, but TV is TV so who knows what he's really like.
Many people suffer personal issues in life and don't know how to seek a solution. Having wealth is extremely useful in these situations, but not a solution in itself nor does it immediately reward you with answers and direction if you don't already know them.
You've presented a version of him that is, to be perfectly honest and from my perspective (and hey, feel free to disagree), hugely judgemental and laden in a bias of your own perspective on his wealth and what that means. He's just fucking sad dude. Sad that someone he loved left him because of his wealth and lifestyle when he probably thought he was living well. On a holiday in a notorious party destination and bored shitless and feeling like he cannot connect with anybody. He can absolutely take steps to fix it and being wealthy as fuck gives him a huge advantage in doing so. But does he know how to fix it? Does he know the steps he should take? Does he know how to satiate those internalised feelings of loneliness and isolation?
Have you offered him advice? Or are you too busy accusing him of not wanting to do anything about it?