Why see this as problematic! Be a good brother . Go before Our Eucharistic Lord and as a family member in love, despite all the gloom ,tell Jesus to be merciful and assist your sister and your family. God is so always in reach. As the uncle to be,dedicate the child and your sister to Our Lord now. When my brothers and sisters,or their children were expectant of children I always dedicate the child and parents to Our Lord and Lady and pray for them. Bless the families involved and pray for the parents. Charity----Love must initiate from each one of us to the other. Take your sister to Church and have the priest bless the child in her womb before the Altar of Our Lady and consecrate Mother and Unborn Child to Our Lady. Do you not think Our Lady would abandon your sister if she is entrusted to her? My dear boy ,life must always include the Divine in our daily life . Invite heaven to partake. . And now my prayer. . Most humble maiden of the Most High,You alone ,of all your kind were highly favored by the Most High God to be Mother of His Divine Son, Our Lord Jesus Christ. I speak to you now and yet then as you on your merciful and charitable act are journeying on to your cousin Elizabeth to give active assistance to her maternity while yet you contemplate your own exalted one. Great Holy Mother you know full well the look of scorn ,the condemnation and ridicule suffered by countless young ,inexperienced,foolish,or misunderstood mothers and mothers to be. I ask you to hold the face of this young mother to be ,in your eye and in your heart. From afar I dedicate this unknown sister of mine to you,I entrust her and her child to you and the Flame of Love of Your Heart. I ask you to lay claim to her child as your own and use this child to expand the Mission that God has entrusted to you. Let the unborn child of this mother bring honor to her family by being a loyal and loving servant to God through your intercession. I entrust the whole of this family to your own Most Holy Family,with faithful Joseph to guide the men and you the women and your Precious Jesus,to bless and draw everyone to Himself. Ave Maria.Full of grace ,the Lord is with You. Blessed are You among women and Blessed is the fruit of Your womb Jesus. Holy Mary ,Mother of God,pray for us sinners,Spread the effect of grace of your Flame of Love to all humanity ,now and at the hour of our death.Amen.Bless God.Blessed be God.Thanks be to God.