My 5 year old kid has bi cuspid aortic valve and currently no issues. does he need flu vaccines in winter. is it a heart condition ?

Flu vaccine: your child should be immunized against the flu whether he has a heart condition or not.

Yes, he should: All children 6 months and older should have a flu vaccine, unless medically contraindicated (please ask his own doctor; there are very few contraindications). Bicuspid aortic valve is not a "heart condition," in that your child may have no symptoms for a very long time, if ever. He should be followed by a pediatric cardiologist (heart specialist) now and throughout his life.