###Human: Suffering from nervousness, unknown fear, loss of concentration and sleep disturbance. ###Assistant: Hi. Your brother is probably suffering from complicated grief reaction or depression. Generally, medicines take some time to have a proper effect. If he has started the medicine in the last one week, then it is better to wait for a few more days.If he has already taken the medicine for more than one week, then there is a possibility that the current medicine is not going to work for him within the current dose ranges. In such a case, we can either increase the dose of medication or change to another medicine which has better potential for your brother.I suggest you provide me the following details: With the above said details, either post a query or book a session for an online therapy for further consultation; so the needful can be done for him. Regarding loss of concentration, it is generally one of the symptoms of depression. So, I hope that with the treatment of depression, it will be corrected.