Once, a Buddhist asked Narayana Guru to convert to Buddhism. (There was a wave of discussion at the time of Vikom Satyagraha). Some people converted to even Sikhism.
Narayana Guru said, “I am already with you!”
The Buddhist was confused. Narayana Guru asked him to recite the name of Budha; in the series, one name is Advaitan.
Buddhism, particularly Vignjanavada in Buddhism, is very close to Advaita. The differences can only be explained by a real scholar. Swamy Tadatmananda is explaining it clearly.