The introduction to the Rite of Baptism for Children has a section entitled “Time and Place for Baptism of Children” numbers 8-14. It is detailed and includes in 8(4):
"… it is for the pastor, keeping in mind whatever regulations have been laid down by the conference of bishops, to determine the time for the baptism of infants.
9. To bring out the paschal character of baptism, it is recommended that the sacrament be celebrated during the Easter Vigil or on Sunday, when the Church commemorates the Lord’s resurrection. …". (From The Rites Volume One, Liturgical Press, 1990, ISBN: 0-8146-6015-0.)
The Rite of Christian Initiation of Adults has:
“26. The entire rite of Christian initiation is normally arranged so that the sacraments will be celebrated during the Easter Vigil. Because of unusual circumstances and pastoral needs, however, the rite of election and the rites belonging to the period of purification and enlightenment may be held outside Lent and the sacraments of initiation may be celebrated at a time other than the Easter Vigil or Easter Sunday.” (The Rites Volume One, Liturgical Press, 1990, ISBN: 0-8146-6015-0, page 43).
Clearly in danger of death Lent makes no difference: “If the infant is in danger of death, it is to be baptised without any delay.” (The Code of Canon Law: New Revised English Translation, HarperCollins Liturgical, 1997, ISBN 0-00-599375-X. canon 867 §2).
“An adult in danger of death may be baptised if, with some knowledge of the principal truths of the faith, he or she has in some manner manifested the intention to receive baptism and promises to observe the requirements of the christian religion.” (Canon 865 §2).