My grandma maid of 3 years has a bf. We saw her holding hands with an man at orchard. How should we approach this?

If we treat her as a normal employee then there should be no issue with her having a boyfriend as long as she only meets him on her off day and doesn't bring him home at any time. I would speak to her and let her know that I am aware that she has a boyfriend. I will also remind her of my expectations of her, set the boundaries (no meeting during work, no excessive calling, etc) and also remind her to be cautious of getting pregnant as it would mean that she has to be sent back.