While I sympathize, if she were a more consistent or established runner (at her current fitness), she wouldn't be in this predicament.
For 2020, she has zero chance of Olympic Team selection, so her attendance at the OT would only be to notch a personal achievement. She may have more OT opportunities if she keeps at it.
Her OTQ chances were done before the race started - it was over as soon as the Houston Marathon refused to place her ahead of the B corral.
I managed elite and sub-elite registration at very large races with similar staggered starts. It is surprising they didn't slot her into the Elite or A corral - the recommendation from her coach should have ensured that. Unfortunately, this sometimes comes down to "who you know" or "who you ask".
If she really wanted to use Houston as a qualifier, she should have slipped into the A corral with her B bib. This isn't that hard to do - not entirely kosher, but no way this would result in a DQ.
USATF rules are cut-and-dry and published. Their hands are tied here.
“Gun” time is the only acceptable method of timing. Chip/net times cannot be used for qualifying. Consideration may be given to “chip/tag” times for competitors with “gun” times extremely close to the above qualifying standards."