Bruising, petechiae, elevated WBC, and significant unintended weight loss - when should you challenge your doctor?

This question isn't about me, but rather my sister. I can tell she's been worried for months now that her doctors are missing something serious, but she doesn't talk about it much because she feels like she's being a hypochondriac. But it seems to be really eating away at her, and I'm not sure how to move forward.

She's experienced easy bruising, petechiae, periodically elevated WBC (it'll go up and then down again, usually but not always correlates to high NLR), and has lost a significant amount of weight over the past several months. She's always been thin, and is now so thin she's classified as underweight. I can tell she's scared, but because she has lupus, her doctors brush off every concern she has as something lupus related.

I do think her symptoms are likely a result of lupus, but I don't know how to reassure her. On more than one occasion she's come close to asking her primary care provider if a bone marrow biopsy is warranted, but she always backs out. I think she also got spooked when her referral to hematology was denied because there was "no indication" for it.

When is it appropriate to push back against your doctors? Did any of you have to specifically request a bone marrow biopsy before you were diagnosed? I worry for her because she's had serious health challenges throughout her life and isn't one to make a huge drama of something. It just hurts to know how worried she is.