Again, show where it is "conspiration theory".
It is, by all what I can say, a reasonable theory indeed, thought out well and covering all known - and now "once known" facts and released materials. He is able to explain it all reasonably and with an easy, simple, elegant theory - and without needing to construct absurd conspiracies and fantasy-enriched nonsense. The scenario sounds perfectly realistic, and it is such that it explains all known pieces of info, in a simple, reasonable and elegant way.
That is much more than you two can show up with: rhetorics meant to prevent a scenario being brought to people's attention and to public discussion that you would not welcome to be true.
If the same theory would end in:
it were the Russians, there would be postings like "I told you so, damn those Russians" by now.
I do not claim the theory by the man is true. I say it is reasonable enough a theory, and sufficiently thought out, to justify giving it serious examination and consideration. And certainly more credit than just claiming "it is conspiracy theory, the man should wear a tin foil hat".