Another sad meme

i'm sorry for your loss. i'm sure you're hurting still. nothing will heal it but time will help ease some of the pain.
i don't know your dad but i know some widowers. i can tell you he hasn't got over your mom's death. he never will. when your mother passed away a part of his heart died too. the hurt for him will always be there. i've known widowers that were remarried for years after their first wife passed away and still cry when they think of their first wife. you may not know it or think it but he probably has cried at night just as much as you have.
the thing is he's lonely. i don't know your mom but i don't think she would want him to be alone. he can't fill the hole she left when she passed on but he can find someone to help ease the pain.
hope this helps you understand him a little better

I can't add much, other than your dad deserves a second chance at happiness. Imagine how difficult it will be for any woman he is involved with, because, conscientiously or not, he's going to compare every wan to your mother. If the time comes and he decides on a permanent relationship, discuss it with him first.