Keeping busy is such a bad piece of advice thats give out to grieving people. When your in the midst of your busyness, you might get distracted enough to forget your pain for a short while, but when the busyness ends.... back comes your grief.
Haven't we all heard someone say "time heals all wounds" or "just give it time." Unfortunately, those words are not true and it's a bad piece of advice to give a grieving person. Time does not heal and if those people try to bury their pain deep inside and never deal with it, sadly they may have trouble thriving socially.
Grieving alone is quite a common thing for people to do, mainly because it's a learned behavior. People often feel like they don't want to burden others with their sad and painful feelings, and end up losing that natural desire to talk about their pain. It's sad to think that emotions associated with pain and distress are expected to be dealt with on your own.
Now matter what someone you know is going through, telling them to stay strong is one of the worst things you can say as it implies that they are not permitted to grieve. Those two words are empty, no one has to try to act strong and put on a brave face, when all as they really want to do is breakdown and cry.
So many of us as children have been taught not to feel bad as crying is immature so it's better to hide that sadness, and many learn that showing emotions is a sign of weakness. When we learn how to understand them.... we learn how to grow.