Hi,
Thanks a lot for sharing this question, I am always looking for new tools to fight depression. I am not sure we can fix a date to end grieving but perhaps we can do something to ease the process. I am grieving my mom who passed away last year. Sometimes I have flashbacks of her in a bad shape and that make me suffer. What I am doing now is that when I have those flashbacks I voluntarely divert my mind to other memories of her I have, particularly right before she got ill ( when she was OK and we were visiting NY city). Then, I feel much better and my anguish disappear.
Ok, I do not know if this is useful, but somehow I think we can be proactive regarding our negative thoughts.
I am sending you a hug