I've have heard that the Sacraments are valid even when the priest is not the most holy person. Personally, I have a difficult time believing this. A corrupt priest would be a dirty container for the Spirit. How could the Holy Spirit act or reside there? I think a priest/Saint's abilities are directly related to their own purity. I will only go to Mass and take Sacraments from a priest I respect and know to be a good person, but that's just me. If sin is a disqualifier for Jesus to work through a priest, then we would have absolutely no sacraments.
And if doubt as to a priest's being a "good person" affected the validity of sacraments, we would never know if we had every received a valid sacrament.
SD
I'm not asking for perfection, just fidelity to priestly vows and freedom from mortal sin. I don't think I'm asking too much. Even I as a lay person can manage this. If a priest can't manage this then he has no business being a priest.