Gen. John Allen also helped Jill Kelley’s sister during custody battle

Both Gen. David Petraeus and Gen. John Allen intervened in the same nasty child custody battle involving Natalie Khawam, the “psychologically unstable” twin sister of Jill Kelley, whose bombshell claims of being threatened by Petraeus’ lover led to the top spy’s resignation last week, the Post has learned. Allen…