Town & Country magazine had a fairly thorough outline of the legal situation although they still, like so many other sources, concentrate on the will and forget the part played by House Laws, which are separate and equally if not more binding. https://www.yahoo.com/lif...can-author-132000376.html
After Prince Richardís death, Gustavís great-uncle laid claim to the Berleberg fortune, claiming that the relationship between Gustav and Carina even without marriage disqualified Gustav as heir. That would explain why Carina seemed to vanish into UK, lowering their couple profile while this was thrashed out.
I would like to point out that while I strenuously disagree with the willís language as written, the fact is that it protected the Berleberg stuff from being grabbed by others. In other words, the will is the whole reason that Gustav and Carina had a castle to marry in, a tiara for her to wear, etc. The will did exactly what it was intended to do: make sure that everything skipped then-baby Prince Richard with remainder passing it on through to future to be born Gustav. It was a wealth preservation instrument, and it worked. The fact is that the will could not have legally been lodged and recorded with the courts of that time, when the grandfather went missing in action, without the language as written.
Now that this is behind them, they can step confidently into their own future.