That is exactly why the congress has waited for an extreme emergency to turn to the courts. They have let Obama get way out of bounds before challenging him.
If the courts don't stop him now, there is no point in having a congress or the courts. If congress puts up any kind of a reasonable argument, the courts should side with them.
Boehner doesn’t have standing. He doesn’t represent Congress. He really only represents a majority in the House of Representatives.
Besides he has other options to check the POTUS. The purse, and impeachment.