Harry Potter and the very different path

Nevile is the BWL and Harry has had a very different up bringing, at Wool's Orphanage.He is very different oh yes indead. His mother Was not Lily Evans no she married Frank Longbottom. But no Harry Parents where not tortured into madness. But why did he end up in an Orphanage. This will not contain a slash paring. it will have parings tho.