Hi,
Welcome to ehealthforum.
Bleeding during or after intercourse could be suggestive of PID (pelvic inflammatory disease), vaginal infection, cervical erosion, presence of polyps etc.
She should consider getting a thorough evaluation done to look for the exact cause for the symptoms. Do not delay in visiting her gynecologist. If infection is detected for her, you should also get treated simultaneously to prevent giving her re-infection. Avoid intercourse while being on treatment.
Early detection and treatment will help in minimizing and treating the problem well. It will also help to ward off future infertility issues.
Hope this helps. Take care.