Definitely see a doctor for a diagnosis. My friend's 15 year old daughter lost her colon and needs to have a bag now because her Crohns was not caught in time. Better to find out what it is so she can deal with it.
This is typical for successful business people. Sounds like a wake up call to slow down and look after herself. Hopefully it's just stress but stress is really the underlying cause of most illness.
If she really refuses to go to a doctor then a change in diet is crucial since certain foods can cause bleeding especially if she's become celiac: dairy, gluten, processed foods, sugar and processed oils, etc. Aloe juice taken internally is very healing but again, this is no substitute for going and getting a diagnosis but some people die before they will do that so these tips are helpful for people like that.
Keep us posted on this!