Interesting, I think you are right. However, you should consult an Estate Attorney to confirm. You should specifically mention "Section 2040(a)" of the tax code, and ask about 'tracing' who paid for it.
<a rel="nofollow" target="_blank" href="
https://www.law.cornell.edu/uscode/text/26/2040">https://www.law.cornell.edu/uscode/text/26/2040</a>
