Jaundice is very common in newborns, and while I know it sounds alarming to you, it's very easy to treat.
Regarding blood transfusions - the family does not have to provide the blood. It's not even as involved a match as an organ transplant, which usually comes from outside the family anyway. Blood for transfustions can be from any compatible donor, and all blood supplies are routinely typed and crossmatched ("type & cross") for a number of factors. It's done by the lab, and every hospital has one. You know those Red Cross blood drives you see advertised? That's what they're collecting. If you want to help, the thing to do is to contact the hospital where the child is, your local hospital or the Red Cross and find out the hours (sometimes easier to make an appointment) to go in to donate blood. It won't go to your nephew (who probably doesn't need a transfusion anyway), but it will go to someone who is a match, just as some wonderful donors provided the blood for every person in your nephew's hospital who needed blood today. Healthy donors can give every 8 weeks.