Hello Thanks for your query.You have not mentioned age of your brother in your query.He has enlarged subclavian lymph nodes on both the sides.Does he have a fever? Has he lost weight very recently?
Please get following investigations done to help to conclude his illness.
1) Haemogram with ESR
2) X-ray Chest
3)Complete ENT check up to find out primary focus.in throat.
If necessary he has to undergo a minor surgery of Biopsy
so that the part of the enlarged lymph node
can be sent for Histo pathological examination and final diagnosis.Please consult some surgeon for detail clinical assessment and further management.