Complex sentence: Privately however, Umbricht learned that the doctors wasn't sure if the cancer surgery was a success or even completely removed from his body and even if it was, his chances of survival was slim at best.
Split into simpler sentences: Privately however, Umbricht learned that the doctors weren't sure if the cancer surgery was a success, or even if it had been completely removed from his body. Even if it was, his chance of survival was slim at best.