We all love the story of the prodigal son. That a loved one can fall far but recover and return is the hope of everyone with a black sheep in the family.
Of course the father, recognizing the sincere repentance of his son, accepts him back into the fold and celebrates the return. However, I think that many people hold out too long for and offer too much to prodigal sons.
"What would Jesus do?" is a fine question to ask when faced with any situation. However, let's not misconstrue Jesus when answering the question ourselves.
In the parable, the father does not keep giving to the prodigal son, hoping against hope that the son will get his life together. The son has to hit rock bottom and suffer for a long time before he comes to his senses, repents, and begs forgiveness.
Recall that in the parable, the son says, "I am no longer worthy to be called your son; make me like one of your hired men." He has to repent truly for his transgressions and demonstrate a clear willingness to forsake the sins of the past and live as the insignificant man whom he has made himself.
Jesus forgives in the face of repentance. He forgave the thief who knew that he was a sinner and defended the innocent Jesus. Jesus told that thief that he (the thief) would soon be with him (Jesus) in Paradise. He said nothing of the other thief who did not repent.