Q: But who sees there is no doer? Isn’t it the ego itself that sees through the illusion of self?

I use the word ‘ego’ to be synonymous with ‘doer’. Because there is a belief in being a doer, there is the notion that ‘I can change this’, ‘I can get somewhere better’, which is the seeking. This seeking is a subtle form of suffering.

When the doer is seen to be false, the seeking starts to collapse, and suffering fades.

To answer your question: who or what sees there is no ego? That which previously saw the ego is that which sees there is no ego. It is never the ego that sees: the ego is a construct of thought, which is always the seen.