Surface part to sheet metal

Maybe somebody knows how to create collar part in order to get sheet metal flat stage

Friend of mine didi that as surface but he can not unfold it

He did try that as sheet metak loft but when cut it didi not get require shape

I attaches test part also and cut have to be made along 3d sketch1 and unfolded as sheet metal part

Can somebody help him please

SolidworksSurfacing