Some of the most important thanks we can give are in response to those who help us during a time of grief. Expressing gratitude to those who help is not only polite, it can be an integral part of the healing process after a loss. After a Catholic funeral service for a departed loved one, a good way to express gratitude to your priest for all his efforts is through a heartfelt thank-you note.
Write a handwritten note. Handwritten thank-you notes generally seem more heartfelt and personal than typed or printed ones.
Keep it short, if you prefer. The priest will understand if writing a long message of thanks is too emotionally difficult, or if you're simply too busy and tired because of family and end-of-life arrangements. A simple message with a sentence or two thanking the priest for his time and for the service will be sufficient, and be appreciated.
Refer to your departed by name. It's possible that your priest may be responsible for many funerals and it will make it easier to remember who is writing to him if you include the name of the deceased early in your letter.
Thank the priest for both his practical and spiritual help. The act of preaching for and organising a funeral service requires both spiritual and logistical work, and for those who do such work, it's nice to feel appreciated for both sides of the equation.
Let your priest know how his efforts helped you. Tell him if you found the service moving, if the funeral helped you and your loved ones with your grieving process, and if there was any part of the homily that you found particularly appropriate and touching. It will mean a lot to your priest if he feels he has been successful in helping the bereaved deal with their loss, as this is a principle part of a spiritual leader's calling.
Close the letter with a blessing. Even if you don't share the Catholic faith yourself, it's good manners to wish someone well according to the traditions of their own religion, especially someone as devoted as a priest. It can be as simple as writing, "May the Lord bless you," before signing your name.