Can anyone tell me please, the benefits to my DD in me continuing to express for her.

I know milk changes after 6 months & although I am fairly certain it's still good for her, saying 'because it's good for her' or 'because I want to' is starting to wear a bit thin

I fed DS2 for 14 months but that was largely a booby thing, whereas DD2 couldn't care less

Is she still getting antibodies etc, is it of any benefit to her immune system still?