Let's consider the following for starters:
1. USA buys more Pakistani exports, specially textiles, than any other country, including Iron Brother.
2. USA has provided billions of dollars in direct and indirect support to many sectors of the Pakistani economy, including the military.
3. The disparity that is growing between India and Pakistan is mainly economic, and USA can do little to prevent that. It is up to Pakistan itself to get its economy into better shape. Heck, even Bangladesh is doing a better job.
4. Crying nuclear wolf is a failed strategy now. There will be no war over Kashmir, nuclear or otherwise.
There is more, but you get the gist.
Pakistan has overplayed its hand disastrously already. Now, crying nuclear wolf will simply not work anymore, and neither will asking for parity with India. That ship has sailed away.