What is the name of this here book?

This book is fromt he POV of a boy whos mother has a degenerative disease (starts with an h?) she doesnt remember things easily. The boy goes about a company that is owned by a man that was friends with his mother. (something like that) and he soon discovers there are children in a secret unknown level who are geneticly engineered and he realizes they are his siblings (not sure ont he siblings/genetic engineering). then the ,man, the children, and the women helping him all disappear.