Switch Hypnosis and Perish song with Rest and Sleep Talk.
Rest-Talk has worked amazing for me with Scald and Ice Beam.
Good item would be: Leftovers
You forgot to post abilities :P
If it has Own Tempo, then you should teach it Petal Dance. That makes it a much better sweeper.
Good item would be: Life orb / Leftovers
Poison Jab is actually better for a nice STAB slot then Ice Punch here.
Good item would be: Black Sludge
EVs: 252 HP / 252 SP ATK / 4 SPD
Work much better.
Hurricane - STAB 100% accuracy in rain
Thunder - Coverage 100% accuracy in rain
Surf - Rain boosted
Roost - Stayin' alive, stayin' alive - ah,ah,ah,ah.
Good item to hold: Expert Belt / Life orb / Leftovers
Change Toxic to Willo Wisp - This will give him more bulk and will still stall opponent.
Change Shadow Ball to Hex. Protect can be changed to Hydro Pump ( Extra power STAB )
And you can still stall with Recover.
Good item: Leftovers