How can one have a child assessed for featel alcohol syndryme and at what age can itbbe diagnosed? and if possible where can we have this done?

Hard to speculate: Such a finding may be suspected at birth from physical findings or later as features emerge. A children's hospital with a genetics department may have staff who are knowledgeable on the syndrome. Since we are USA based & have no information on your local healthcare system you need to contact a local doc for such information.