upekkha100 asked: “Can someone be able to radiate boundless metta to all sentient beings to that level of a brahma, when they still have kama raga?”
You have given the answer below that too.
When one has extreme version of kama raga (abhijja), the power of the metta bhavana is the weakest. One is just reciting without much effect.
– It is stronger when abhijja is reduced to kama raga stage.
– It is even stronger when one has no kama raga, but has rupa raga and arupa raga left.
– It is stronger when only arupa raga is left.
– It is strongest when all are eliminated by removing both tanha and avijja (i.e., for an Arahant).
Put it in another way, the javana power of a citta is increased as one gets rid (or at least suppresses) avijja and tanha.
– Of course, removal is better than suppression, AND removal requires the comprehension of anicca nature (Tilakkhana).
P.S. “A Simple Way to Enhance Merits (Kusala) and Avoid Demerits (Akusala)“