I'm not going to comment or judge your family's situation. I can only comment on Church teaching...and even that I will stop short of fully explaining.
I will say this: Eggs are one thing. Sperm cells are other things. Those are pre-new-life biological elements.
Post fertilization, you have a human. At that point, a new life exists. Basic rules of humanity and non-barbarity apply at that point.
I do not bother myself with the theological reasons underpinning the Church's views on pre-life procreative proscriptions. I just accept the authority of the Church on them. So, I will have to defer to someone who has more of a theological background on those issues. The life side of the equation is quite simple, though.