As the "+" or "-" in the blood types does not make a difference in kidney donation, but DOES make a difference in blood donation, not all kidney donors could also give blood to their kidney recipient. Likewise, not all kidney donors are able to donate blood. For example, since I had hepatitis-A some years back the Red Cross will never accept my blood for transfusion, but I was able to donate a kidney without any problem. So you may or may not be ABLE to donate blood to your recipient.
As to whether blood from the kidney donor would be especially helpful to the recipient, I have no idea.
Hope this info helps.
Fr. Pat