He is running Wish. Blissey is better at passing Wishes to companions in order to keep them alive, because she has more HP.
This being said, I would recommend removing Metagross: since Steel is not resistant to Dark and Ghost anymore, now Metagross has an insane amount of weaknesses, and this is a big problem considering that it is a scarfer. A lot of Pokemon can switch into the correctly predicted move, take a hit and kill back. Since you have Jolteon with Volt Switch, I'd recommend something with U-turn: Greninja comes to mind as it is one of the best Spikers of this generation, you could put Stealth Rock on Skarmory over Spikes (and while you are at it, Whirlwind over Toxic, phazing is needed to get rid of those set-up sweepers) and give Spikes to Greninja... You'd have yourself a great momentum core with Jolteon and Greninja, and you'd also be able to set up a lot more hazards.
The set for Greninja would be:
Greninja (M) @ Life Orb
Ability: Protean
EVs: 4 Atk / 252 SAtk / 252 Spd
Hasty Nature
- U-turn
- Dark Pulse
- Ice Beam
- Spikes
Finally, since you are running Wish on Blissey as a recovery move, you might want to run Protect over Toxic: not only Protect is great to scout opponent's moves (specially in case you face a choiced Pokemon), it also allows Blissey to easily restore her own health with Wish, negating the charging turn.
Oh and... That set for Absol is bad. It can maybe work with your hacked Speed Boost Absol (I read that post ) but Mega Absol needs offensive coverage. Detect is absolutely not needed, remove it and toss in either Psycho Cut or Play Rough. And while Night Slash and Sucker Punch have their logic (you's use Slash against defensive Pokemon who are not going to attack you, playing around Sucker Punch) Megahorn is generally a better coverage option over Night Slash.
This is all. I hope this post proved helpful