Menma secretly despised Naruto, for one reason: Jealousy. It was slightly annoying how his twin had such a good life, and how he was surrounded by so many... friends. Though at times, Menma wanted friends but other than that, he loathes the word so much he wish it would climb to the mountains and die. But that won't happen.... cause it's a word.
Anyways, remember when Kasumi said,

"I'm on a specific mission for the Akatsuki, even most of them were dismantled"

That... was a lie.

There was only one reason why she did that was because Menma payed her a fortune to do so. If Kasumi would've known she would die doing the deal, certainly she would've discarded her offer. Turned out, Kasumi dying by the hand of Team 7 was part of his plan. Even if it didn't turn out, he had a plan B, which was now wasn't necessary.

The last thing he needed to do was to break him even more.