He is pointing out that Republicans have controlled the presidency for 24 of the 30 years that Roe has been in effect.
Also, it was a GOP stacked court that created the Roe decision, a GOP stacked court that upheld it (Casey). It is worth noting that it is a GOP stacked court (5 Catholics no less) that just applied Casey and Roe in Carhart.
My understanding is that he subscribes to your idea of proportionate reasons, that is, accepting some evil positions for pragmatic good results, but asserts that voting GOP has produced no positive results on the question of abortion (the opposite even, since it was a GOP majority court which made the abomination a constitutional right, likewise a GOP majority court that upheld it), but has created other compromises on fundemental moral issues which the Church has, like abortion, called non-negotiable.
I think you are both incorrect, but respect your following your own moral consciences in the matter. However, since your pragmatism is not producing any tangible results, I do respectfully ask, which is more important to you, stopping abortions or electing Republicans?
You have stated you will compromise on the former, but I have seen nothing to indicate that you are willing to compromise on the latter.