Hello and welcome to the forum. Thanks for your question. Are you checking for a family member or friend? It sounds like the only symptom that has you worried is the unexplained weight loss, correct? Have they been to a doctor for a whole body physical? That may be a good place to start. Any GI issues that you know of? Any type of GI issue can lead to weight loss. Even if subtle. Issues with thyroid is another common reason to have weight loss and the symptoms could be subtle. This article that you may copy and paste has a whole list of possibilities to consider looking into for this person. https://www.medicalnewstoday.com/articles/326417 Please check that out and see if any sound like they could match. And again, a physical would be a good idea for this person.