What exactly is google chrome helper? Malware?

That is normal for Google.

• Google products including Google Chrome and Google Drive will burden any Mac regardless of its age or configuration. It litters a Mac with a plethora of root level system modifications in the same manner as a virus would, if such a thing were to exist, which it doesn't.
• Google derives essentially all its revenue from advertising. Their products are "free" because you are the product Google sells.
• Google Chrome was designed for the sole purpose of harvesting your personal information.
• If Safari does not meet your requirements, I suggest Firefox. Unlike Chrome, Firefox does not alter a Mac's operating system, does not demand full-time root access for purposes known only to it, is not designed to harvest your personal information, and is not known to cause the degraded performance that Google Chrome is notorious for causing.
• If you require Chrome and expect acceptable performance from your hardware, expect the need to replace it with newer hardware frequently.

See if this helps:

"google chrome helper" using too much CPU?

Personally, I do not use any Google product because I do not agree with their business model/philosophy.