A desperate Mexican single mother, looking to win back custody of her son living in America, kidnaps a US border guard and uses him as a coyote, unaware that her hostage is the Homeland security secretary’s nephew.

The MC comes across as farcical (good for comedy) but also insane to think this plan would work (might also be good for comedy, can't say). Ultimately, the suspension of disbelief is going to be the biggest problem. If this is an Austin Powers style OTT 'anything goes' comedy, then sure any plan will do, but if this is meant to be a more gritty/reality based comedy I doubt the plan will work.

"When her Ex kidnaps their son and takes him to America, a desperate Mexican mother forces a boarder patrol agent to sneak her across the boarder, unaware the man's father is the head of homeland security."

While the concept strains credibility, it's being played for comedy, not drama. ?Maybe it will work.

The devil -- and comedy -- is in the details. ?I assume you've done you're homework.