Essential community! Subscribed and will try to help people, though I am also a noob at lemmy. But yes, I agree that this sort of community is extremely helpful and could vastly improve lemmy.

Pay attention to her “bids for connection”. When she asks something, even if it is something simple, such as a request to look at a meme on the phone, try to accept the bid and do look at her meme.

Also, why not just ask her? “Hey sis, I see that you are unhappy with the way I treat you. I am sorry, I will try to do better. Can you tell me what it is that you want me to do more?”