Hi.. Thanks fr the query.. As per your complain first thing that I can understand is that your sister is having decayed teeth that is causing weakening of teeth and breaking into small pieces.. Secondly bleeding from gums on bruising too hard can be due to traumatic injury to the gum mucosa leading to laceration and bleeding.. There is also a possibility that she has infection in her gums leading to inflammation and inflamed tissues bleed even on lightest stimulation... Inflammation of the lower lip can be due to injury with toothbrush or can be due to other causes like lip biting, eating some hard foods or burning with hot foods.. For inflammation doing ice compresses is a good choice as it will help in reducing inflammation.. You can also give her Ibuprofen for relief.. For breaking teeth and bleeding gums you need to consult a Pedodontist and get evaluated and in case of multiple decays doing filling or Pulpectomy depending on the condition of teeth can help.. In case of infection in gums a thorough full mouth scaling and gum paint massage can help.. Hope your query is resolved.. Thanks and regards.