When losing a loved one, people who are affected grieves differently. Others can grieve in a short period of time, while some grieves longer, even taking years. Should we criticize them for their long grief? Of course not! We should be sympathetic and comforting towards them.
We all have different ways to move on from painful situations so we should understand each other. Our EQ (Emotional Quotient) can tell how one can accept things.
During Biblical times, there are some people with integrity to God who grieved for many years. One is the righteous Jacob who grieved over his belief (his other son made him believe that) that his son Joseph died. His grief even took years, but God didn't rebuke or criticize him.
If you are grieving, just let it out. Do not ignore it. Other people who tried to supress their grief ended up getting psychologically affected in the future. You can cry it out, express it to a confidant because it can help you to feel better.