The Friar is to blame for all of the drama and deaths that went on in Romeo and Juliet. If the Friar wouldn't have married Romeo and Juliet then none of the drama would have began. The Friar shouldn't have given the potion to Juliet, and he shouldn't have lied to the Capulets about why Juliet wouldn't marry Paris. The Friar also shouldn't have gone along with new plans without informing Romeo on what his part was first.
Friar Laurence shouldn't have married Romeo and Juliet without the consent of the families even though he had good intentions doing it. If the Friar wouldn't have married the two "love birds" then nothing would began between Juliet and her father. If the friar would have just stayed in his own business and not try to be a "hero" and solve the issues involving the Montagues and the Capulets, then most of the drama would not exist. If the Friar wouldn't have gotten the crazy idea that by marrying a Montague and a Capulet to try to fix the families issues then Friar Laurence wouldn't have let the two get married min the first place. The marriage of Romeo & Juliet just was a beginning of the many problems that were problems yet to come farther into the story.
Friar Laurence shouldn't have gave Juliet the potion to make her look like she was dead. Juliet didn't even know if it was really just going to make her look dead or if it was really going to kill her, either way Juliet would never be able to see, speak, or have any interaction with her family and Romeo. The friar also shouldn't have lied to the Capulets about why Juliet wouldn't have married Paris. If the friar would have just came clean when this whole thing started to become a complete mess he could have solved all of the drama that was beginning to unravel. The friar should have just came out and told the Capulets that he married Romeo and Juliet and that Paris couldn't marry Juliet because she couldn't wed again.
After the Friar thought he had everything solved everything went down hill. The wedding date changed to an earlier date, and the friar didn't inform Romeo about the whole thing. If Romeo would have known about the plans for going back to Verona then they could have been able to get into the tomb and awake Juliet. If the friar would have just stopped for a moment and thought about what he was doing not telling Romeo about the changes. Without Romeo knowing anything about the "death" of Juliet then he would have realized how necessary it was for Romeo to be informed of this.
There for if the Friar would have just thought about the consequences to all of his actions then he could have solved all of the drama created by his own actions. If the Friar wouldn't have let Romeo and Juliet get married, if he wouldn't have given Juliet the potion to make her look like she was dead, or lie to the Capulets about the marriage, and if Friar Laurence would have informed Romeo about the new plans to bring them together. Doing so he would have saved a lot of people's lives and none of the drama that was started would have started.