I don't think his sister is actually watching him as a ghost... it's his subconcious, he is conflicted because of his feelings for the girl and also his grudge he has with humans, maybe this dream is, in a way, him talking to himself, to try and put his thoughts in place. Who she should prioritize, honoring his dead family or acknowledging his love for the girl? ╮(￣▽￣)╭ (just my interpretation tho)
I don't think his sister is actually watching him as a ghost... it's his subconcious, he is conflicted because of his feelings for the girl and also his grudge he has with humans, maybe this dream is, in a way, him talking to himself, to try and put his thoughts in place. Who she should prioritize, honoring his dead family or acknowledging his love for the girl? ╮(￣▽￣)╭ (just my interpretation tho)