HIV risks with open wound

A friend of mine suffered a head injury from skateboarding.  It was pretty bad and he was bleeding quite a bit.  Afterwards he started getting paranoid about getting HIV.  He hasn't gone for any tests but he thinks that when he was cleaning up before going to the hospital, he may have been exposed to the virus.  He said his friend was scrubbing his head and spit into the rag to try to scrub the blood out.  If his friend did have HIV and there were open sores resulting in their blood mixing; what are the chances of him contracting HIV?

[Teak]

Zero. Saliva is not infectious.