In the recount that the Venerable posted, it was told to Ajahn Mun in private discussion. Ajahn Mun invited Kruba SiVichai to come to stay with him, and he would end all suffering, and Kruba SiVichai declined, stating his path and his confirmation. Ajahn Mun praised him, saying it was the utmost pinnacle that a human could achieve.
It does not seem like something that he was proclaiming to others publicly, but eventually word probably spread after Ajahn Mun told his closet diciples, and after they told their disciples, etc. etc.
I believe this refers to the fact that
someone declares their intention to be or follow the Bodhisatva path to a current Buddha. So (now) the previous Buddha would have confirmed this path to the ‘current’ Bodhisatva.
He could have been a direct student of Kruba Siwichai but it would have been in a previous birth. He was a disciple of some of his students though. If you dig around on the internet you can find a few brief decent-subpar bios in English.
He was a disciple of Luang Pu Doo. It is taught by many in the Thai Forest Tradition that Luang Pu Doo was an incarnation of Metteyya, along with Somdet Toh and Luang Por Thuad. There is a photo of Tan Ajahn Dtun, Tan Ajahn Piak, and Tan Ajahn Anan paying respects to him as young monks.
The fb page linked above has some teachings of his translated into English as well as some info about him. Right now he is finishing up one of his many 3 year 3 month 3 day retreats.
He has done many awesome things in his life at 15 he remodeled many temples and cetiyas. At 18 he walked from Northern Thailand all the way to Nepal, spending the rainy season on retreat in a cave. He also never wears shoes and directs many charity followers. I intend to pay respects to him someday but since the rescue of the Thai kids in the cave it is very hard to do. He has millions of disciples throughout Yunnan, Bhutan, Nepal, Burma, and Thailand. A bit like the Dalai Lama of SE Asia.
There are some better resources but with a few minutes of noodling I found these. I hope a real biography in English is produced. He’s had an incredible life.
