Brief Answer:
Mostly due to tuberculosis
Detailed Answer:
Dear Friend.
Hi , I am Dr Anshul Varshney , I have read your query in detail , I understand your concern.
If you talk practically , these things can occur at any stage.
However , if we go according to Center of disease classification , they don't mention
night sweats and
dry cough as a part of there classification. but if you still wanna know , i would say from CDC Stage 2-3.
Night sweats can occur in
HIV infection as a result of co-existing Tuberculosis infection , so stage is not a matter in that case , as a person with HIV can have tuberculosis at any stage.
If we talk about dry cough , it is usually due to secondary infections like
Pneumocystis pneumonia , tuberculosis , fungal pneumonia's.
So , this should not be a concern that what stage it is with these symptoms , concern should be why they are.
I advise you to get Chest Xray , Hemogram , CD4 counts of the concerned person for a better diagnosis and treatment
This is my personal opinion based on details available here. If you still have any query you may please ask me.
Stay Healthy.
Dr Anshul Varshney , MD