This post continues my series of short answers to common questions about Catholicism. For the previous parts in the series, see the "Catholic Q-A Series" blog label.
I know Constantine waited until his death bed to be baptized. Could it work that way to live a life of sin and then be baptized right before death?
Yes, as unfair as it sounds, someone baptized at the very end of his life will go to heaven, even if that life was filled with many sins. We have to uphold the power and efficacy of Baptism. If a person is baptized with water in the Trinitarian formula, his sins are forgiven. Period. He's a child of God now. Everything that would destroy the divine life within him has been removed.
This sort of deathbed salvation reminds me of the parable of the workers in the vineyard (cf. Mt 20:1-16), where those who worked only in the last hour of the day received the same pay as those who worked all day long. Let us not "grumble at the householder" (vs. 11) or "begrudge his generosity" (vs. 15). God can do what He chooses with what belongs to Him.
As an aside, such a person will probably have to undergo a significant purging first (that's what Purgatory is) but heaven will be his. I say this purging is likely because, while baptism washes away all sin and it's punishment, that person will still have his attachments to sin (by that I mean, his tendency to find certain sins very appealing) and concupiscence (his tendency to sin at all) and his other bad habits that he developed and nurtured over many years.
If a divorced person remarries with out an annulment, is that person living in sin his whole life after that? What if he isn't Catholic?
The Church holds everyone to the same standard here. It is a serious sin to divorce and remarry. The person who does this is "living in sin" only so long as he engages in marital relations with the new spouse. If someone in this situation confesses his sin and vows to cease all marital relations with the new spouse (to live "as brother and sister" is the common phrase) then that person is no longer said to be "living in sin" and is free to receive Communion.
What is a gentle way to respond to those who say "Jesus isn't on the cross anymore" in reference to the crucifix?
You could always say, "I know." Haha, seriously though, I wrote a blog post a while back that should give you all the information you need for the next time this comes up. See "Why Do Catholics Keep Jesus on the Cross?"
Do indulgences even exist in Catholicism and what are they anyways?
Yes they do. An indulgence is the remission of the temporal punishment that is due to sin. Since human beings have a temporal dimension (our bodies, this life we live) and an eternal dimension (our souls), the sins we commit have a temporal effect and an eternal effect. When you receive absolution in the confessional, the eternal effect is remitted or removed. When you perform your penance, the temporal effect is removed. But, sometimes people don't adequately atone for the temporal effect of their sin. Sometimes they forget to do their penance, or they don't do penance for the sins they don't confess. This sort of suffering, in the world, builds up and must be remedied. Indulgences are the remedy.
Beyond that, the best thing to do would be to read what the Catechism has to say on this subject. See nos. 1471-1479. I realize this subject can be confusing. If after reading this you are still a little foggy on what indulgences are, just let me know.