Can you more elaborate like how you get the path and all using remote file info
Before posting, please read how to report bug or request support effectively.
Bug reports without an attached log file are usually useless.
WinSCP .NET assembly does not support "downloading" remote file contents to memory.
All you can do is to download the file to a local temporary location and read it to the memory from there.
using (Session session = new Session())
// Download to a temporary folder
string localPath = Path.GetTempFileName();
// Read the file contents
byte contents = File.ReadAllBytes(localPath);
// Delete the temporary file