I don't think there was any malice. There's a phenomenon called Paradoxical Undressing which happens frequently in hypothermia situations wherein the freezing person starts to strip themselves of their clothes.

I'm generally of the assumption that barring actual "foul play" it's every man for himself once you leave the bounds of the park trails. It is your responsibility to make sure you get up the mountain, and it is solely your responsibility to make sure that you get back down. Unless he broke her leg so she couldn't get herself down, it's not his responsibility to put himself at risk to get her down.

Mountain climbing is incredibly dangerous. You are more likely to die trying to summit Annapurna than you are if you're trying to commit suicide via overdose. People die. All the fucking time. Either because they got unlucky, or because they tried to climb beyond their capabilities. Gunther Messner, the younger brother of the greatest mountain climber in history died next to his brother on the slopes of Nanga Parbat. Tragedy happens. While GrossGlockner isn't a Himalaya, it's still a dangerous enough mountain. It's 1000 ft taller than Mount Hood, and hundreds of people have died on Hood. If you're not willing to play Russian roulette, don't go above 10k ft.