First things first: It is very common for children your son’s age to suddenly have fears about death and dying. Sometimes they have fears about themselves and sometimes about other people in their lives. Unless it persists for a couple months or causes him distress that is significant enough to interfere with his daily functioning (at school, socially, behaviorally) then I do not see a need to seek professional help.
The key from a parenting perspective is to remain patient, comforting and reassuring. It is 100% okay to discuss death in factual terms (without the gory details) with a seven-year-old. For example, you can acknowledge that we all die at some point but assure him that he is going to live a long, long time before he will die. The fact that you can’t guarantee this is not important – it is, in all likelihood, true. Be careful not to criticize or minimize his fears. Let him know that it is okay to worry sometimes, tell him you love him and then see if you can find something for the two of you to do together that will get his mind off it. Most likely it will cease being an issue before you know it.
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