A question about blood type and conceiving?
No, blood types do not impact conceiving. Rh factors might, although not in the first pregnancy. If a mother is Rh- and the baby is Rh+, it can endanger future pregnancies. So as a precaution Rh- mothers have a Rhogam shot mid-pregnancy, and if the baby is Rh+, they get a second after the birth. In your friend's case this isn't applicable because she's Rh+.
There is nothing about blood type that will prevent pregnancy from happening. HOWEVER - if the mother is RH negative and the father is RH positive, then if the baby has RH positive blood, it can complicate the pregnancy. There are issues with RH incompatibility that need to be dealt with during the pregnancy. There are injections that make the pregnancy possible without harm to mother or baby. Now, in this case, the mother is RH positive, so it doesn't really matter what blood type the father is since it only matters when the mother is RH negative.
In years goine by, each person, especially the man had to have a blood test by a doctor to determin something I don't remember, in his blood, which would affect the baby adversely. They finally stopped this, for some reason.