From the rest of your letter I gather that your acquaintance is now truly ill, with her past dogging her. Her family would do well to get her treatment, while explaining her bizarre past. I had it, and it is very uncomfortable, believe me. Phlebitis usually involves clot formation along with the inflammation. You don't mention clotting in your letter.
Superficial phlebitis locates the inflammation in surface leg veins.
Veins buried more deeply pose the threat of clotting and of a bit of a clot sweeping upward into lung circulation. Blockage there would be calamitous. That does not happen in superficial phlebitis. You spoke the truth about the pain of superficial phlebitis. You can feel the inflamed vessel as a hard cord, with surrounding skin red and tender.