I agree with hector 100%. If I cut myself I treat it like a biohazard. Your friend should not let ANYONE except medical professionals tend to his open wounds. Period.
There are no stats on the scenario described, IMO almost zero, if your worried wait the proper amount of time and get tested, it is the only way to know for sure
Transmission / Exposure
How is Hepatitis C spread?
Hepatitis C is usually spread when blood from a person infected with the Hepatitis C virus enters the body of someone who is not infected. Today, most people become infected with the Hepatitis C virus by sharing needles or other equipment to inject drugs. Before 1992, when widespread screening of the blood supply began in the United States, Hepatitis C was also commonly spread through blood transfusions and organ transplants.
People can become infected with the Hepatitis C virus during such activities as
•Sharing needles, syringes, or other equipment to inject drugs
•Needlestick injuries in health care settings
•Being born to a mother who has Hepatitis C
Less commonly, a person can also get Hepatitis C virus infection through
•Sharing personal care items that may have come in contact with another person’s blood, such as razors or toothbrushes
•Having sexual contact with a person infected with the Hepatitis C virus
Can Hepatitis C be spread within a household?
Yes, but this does not occur very often. If Hepatitis C virus is spread within a household, it is most likely a result of direct, through-the-skin exposure to the blood of an infected household member.
What are ways Hepatitis C is not spread?
Hepatitis C virus is not spread by sharing eating utensils, breastfeeding, hugging, kissing, holding hands, coughing, or sneezing. It is also not spread through food or water.
http://www.cdc.gov/hepatitis/C/cFAQ.htm
There was no blood to blood exchange between him and you so there is zero chance of transmission and infection. Hepatitis C is a blood borne virus which means it is passed from the blood of an infected person to the blood of a non-effected person. So you have nothing to be concerned about.
Tell your friend to take responsibility for of his medical issues. He should educate himself and take steps to prevent others from being exposed to his blood and the hepatitis C in it.
Until he is cured of his hepatitis, he is responsible for not spreading the virus to others. No one but himself and a properly protected health care worker should ever be exposed to his blood.
Hector