A standard twin mattress is 39 by 75 inches. A king is 76 by 80 inches. This means that a headboard for a king bed is going to be about 76 inches or wider, plenty wide enough to go along the length of a twin bed. Headboards are often slightly wider than the bed for which they are made.
Hemoglobin, Hematocrit, Blood Count. In order to donate blood, a woman must have a hemoglobin level of at least 12.5 g/dL, and a man must have a hemoglobin level of at least 13.0 g/dL. For all donors, the hemoglobin level can be no greater than 20 g/dL.
But even if the blood types are not compatible, you may be able to find a program that allows proxy donors. This is when someone who doesn't match the intended donor can still donate the organ for someone else's use, and the intended donor goes to the top of the transplant list.