Let me briefly describe the background of my question:
I have been staying at the house of my cousin and her husband for a few months, and I will be leaving to return to school in a couple of weeks. My cousin is a "non-denominational" Evangelical from a Church of Christ background, and her husband is a cradle Catholic. However, since I have been here it is apparent that she has succeeded in pulling him away from the Church, or at least from attending Mass on Sundays, instead going to services at her non-denominational megachurch.
I love my cousin, and she has been very generous in allowing me to stay in her home for such a long period. She is also not anti-Catholic, and she is a very reasonable person. About a month ago I gave her "Rome Sweet Home" by the Hahns, and she has been reading it and discussing it with me on occasion. She seems open to Catholicism; however, I know she is reluctant to move in that direction for reasons that are not so much intellectual as having to do with emotions and her relationships. Basically, she is very attached to the youth group at her current church and fears losing those friendships. Also, she fears that her mother-- who was in many ways manipulated into leaving the Catholic Church and joining the Church of Christ in college-- would be "heartbroken".
My question is two parts:
1) They have a one-year-old daughter, whom they have not yet baptized, instead waiting for a "believer's baptism" when she reaches the age of reason. If there seems to be no chance of them baptizing her in the near future (dad has basically given up on that), should I take matters into my own hands and do it myself, secretly? I know that sounds kind of crazy, but I am concerned for my little niece's eternal salvation.
2) Is it at all advisable (or obligatory) for me to inform my cousin's husband that skipping Sunday Mass is a serious sin (or could be one)? I honestly don't think he is aware of this. He was poorly catechized, and seems to think that one church is just like any other. My concern here is that I don't want to alienate him from the Church, and I don't want to end our relationship. I am also in a bit of a precarious position as a guest in his house.
Any advice is greatly appreciated. God bless.