HIV is not transmitted in the ways you imagine. All over the world, people live in households of HIV infected people. They hug, kiss, and share bathrooms, kitchens, towels, and eating utensils with the infected people. Yet in the quarter century of the known HIV/AIDS epidemic, with millions of infected people worldwide, not one household contact is known to have caught HIV, if they did not have sex or share injection equipment with the infected person. Not one.
Can I imagine a possibility from the sort of events you describe. Sure. I can also imagine getting hit by a meteorite, but I don't go out of my way to take precautions against it.
On top of all that, you don't know that your cousin has HIV. If he is heterosexual and not an injection drug user, he probably is at low risk, isn't infected, and never will be. But even if he had known AIDS, you would not need to take any precautions to protect your kids or anyone else.
Bottom line: On several grounds, your worries are unwarranted. If you enjoy your cousin's company, and if your kids like him, please don't try to limit his visit or change his behavior. It simply isn't necessary.
Regards-- HHH, MD
To help you out even more you said this person shaved earlier...cuts would not still be bleeding. So any idea that he pushed blood into a cut would simpley just not happen.
That's all for this thread.