is it valid the First Communion of a child or a baptism that has one of the Godparents to be an atheist? (baptized Catholic but stop believing)
If the child’s godparent stops practicing the faith, that is not the child’s fault and it has no impact on future sacraments.
If you are asking if a baptized Catholic who is now an atheist can be a godparent, the answer is no. But if they were for some reason able to stand up as the sponsor at the baptism that does not make the baptism invalid.
a new God Parent must be a practicing Catholic in good standings with his/her Parish.
An atheist would not meet this requirement.
NOTE: If a child getting first communion who was baptised years ago has a God Parent who is now an atheist, they don’t get a new God Parent. Though it would be wise to keep that atheist from influencing the child. When the child receives Confirmation, he/or she will need a new sponsor, one who is in good standings with the Church.
Hope this helps and God Bless.
Only one sponsor is required at baptism. That person must meet the requirements of canon law. A baptized non-Catholic Christian may appear but would be considered a witness.
PART I : THE SACRAMENTS
CHAPTER IV : SPONSORS
Can. 872 In so far as possible, a person being baptized is to be assigned a sponsor. In the case of an adult baptism, the sponsor’s role is to assist the person in Christian initiation. In the case of an infant baptism, the role is together with the parents to present the child for baptism, and to help it to live a Christian life befitting the baptized and faithfully to fulfill the duties inherent in baptism.
Can. 873 One sponsor, male or female, is sufficient; but there may be two, one of each sex.
Can. 874 §1 To be admitted to undertake the office of sponsor, a person must:
1° be appointed by the candidate for baptism, or by the parents or whoever stands in their place, or failing these, by the parish priest or the minister; to be appointed the person must be suitable for this role and have the intention of fulfilling it;
2° be not less than sixteen years of age, unless a different age has been stipulated by the diocesan Bishop, or unless the parish priest or the minister considers that there is a just reason for an exception to be made;
3° be a catholic who has been confirmed and has received the blessed Eucharist, and who lives a life of faith which befits the role to be undertaken;
4° not labor under a canonical penalty, whether imposed or declared;
5° not be either the father or the mother of the person to be baptized.
§2 A baptized person who belongs to a non-Catholic ecclesial community may be admitted only in company with a catholic sponsor, and then simply as a witness to the baptism.
As long as these rules are followed and the baptism is valid at the time it was celebrated, it remains valid.