One does *not *want to seek have the baptism done outside full communion with the Catholic Church -the child has the right to be Baptized into full communion -to be a Catholic.
When another Christian who is not Catholic Marries a Catholic Christian - they are informed of the Catholics Obligation in this matter.
Here from Canon Law:
1/ the Catholic party is to declare that he or she is prepared to remove dangers of defecting from the faith and is to make a sincere promise to do all in his or her power so that all offspring are baptized and brought up in the Catholic Church;
2/ the other party is to be informed at an appropriate time about the promises which the Catholic party is to make, in such a way that it is certain that he or she is truly aware of the promise and obligation of the Catholic party
vatican.va/archive/ENG1104/_INDEX.HTM
It is in “legal language there” cause it is well Canon Law. But it relates the reality involved.
Certainly things need to be treated with great love and gentleness and work for a peaceful solution. But I note the above for they may have forgotten that when they married such is part of the obligation of our Christian life.
Ones Pastor can be a good assistance here (and to help avoid marital strife etc)
Catechism of the Catholic Church:
1634 Difference of confession between the spouses does not constitute an insurmountable obstacle for marriage, when they succeed in placing in common what they have received from their respective communities, and learn from each other the way in which each lives in fidelity to Christ. But the difficulties of mixed marriages must not be underestimated. They arise from the fact that the separation of Christians has not yet been overcome. The spouses risk experiencing the tragedy of Christian disunity even in the heart of their own home. Disparity of cult can further aggravate these difficulties. Differences about faith and the very notion of marriage, but also different religious mentalities, can become sources of tension in marriage, especially as regards the education of children. The temptation to religious indifference can then arise.
1635 … the Catholic party confirms the obligations, which have been made known to the non-Catholic party, of preserving his or her own faith and ensuring the baptism and education of the children in the Catholic Church.
1636 Through ecumenical dialogue Christian communities in many regions have been able to put into effect a common pastoral practice for mixed marriages. Its task is to help such couples live out their particular situation in the light of faith, overcome the tensions between the couple’s obligations to each other and towards their ecclesial communities, and encourage the flowering of what is common to them in faith and respect for what separates them.
scborromeo.org/ccc/p2s2c3a7.htm#1633