It might be needed well beyond the initial period, especially for the widowed. Encourage others to visit or help. Usually one visit will overcome a friend's discomfort and allow him or her to contribute further support. You might even be able to schedule some visitors, so that every one does not come at once in the beginning and fails to come at all later on. If the mourner doesn't feel like talking, don't force conversation.
Silence is better than aimless chatter.
The mourner should be allowed to lead. Be a good listener. When suffering spills over into words, you can do the one thing the bereaved needs above all else at that time - you can listen. Accept that too. God will manage without your defending him.