It's normal for the bereaved to feel depressed, but these feelings can develop into a more serious problem, if left unchecked for an extended period of time. Tell the person you are concerned.  Studies suggest that the most intense feelings of grief usually last about six months, although it varies from person to person. If more than six months has gone by and the person does not show signs of any improvement, or if her symptoms have gotten worse, she may be experiencing complicated grief. This is a continual, heightened state of grief that keeps the person from processing emotions and moving through them. It may also be known as prolonged grief disorder. Recommend seeking professional help if you notice any of the following: difficulty functioning in normal activities, alcohol or drug abuse, hallucinations, withdrawal and isolation, self-harm, and talk of suicide. Contact local organizations and groups to ask for guidance helping your friend. Recommend to your friend that they should attend support group meetings and offer to go with him or her. If you think your friend will decline, you may even try telling him or her you'd like to join the group and ask them to go to support you. Stay in contact and offer words of encouragement. Grieving is an ongoing process, so the bereaved will likely need extra support for at least several months.  Help your friend be prepared to handle future triggers and be prepared to offer extra support at those times. Anniversaries (of death or marriage), birthdays (the deceased's, as well as those of the living), special events (weddings, graduations, births, or any event the deceased would have participated in, or would have liked to participate in), holidays, and even times of day (for people who had regular well established routines with the deceased) can all be triggers. You can help your friend manage triggers by planning activities to distract from them, establishing time during events to briefly reminisce about the deceased, and creating new traditions and routines.

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Write a summary of the previous text in Vietnamese:
Quan sát dấu hiệu trầm cảm nghiêm trọng đòi hỏi phải được can thiệp. Tìm kiếm nhóm hỗ trợ gia quyến của người quá cố. Tiếp tục giúp đỡ người đó một thời gian dài sau tang lễ.