I am also somewhat baffled by the Aikido kanji with Aikijitsu written right next to it. Especially since this style is headed by a native Japanese who is still based in Japan. Maybe this person put up the web site without his teacher's guidance.
I get the impression that by calling his school/style Butokukai, he has the goal of implying that perhaps his rank came from the DNBK. I doubt that, ot it would actually state that.
Check out the school. If you like it and can learn what you want to learn there then go for it. But look into the lineage and all claims made. Ask about the lineage, where that 7th Dan came from, etc. You can always come back here to ask more questions.