Can a non-engineer start a tech company?

No, you are doomed to flipping hamburgers. ;-)

Actually, you may have a better chance of success. A successful business needs a bunch of other skills other than engineering like fund raising, marketing, sales, contacts. One thing you must do is find a top-notch engineering partner that you trust. I have had to help a couple of startups that handed off development to a cheap overseas company and got back a subpar product delivered late.

A non-engineer can join an engineer to start a tech company. But need to know enough to be able to understand what co-founder is doing in engineering.

It's rare a pure tech company to have been started by a non-engineer especially something big like Google.

absolutely, just surround yourself with good engineers and experienced startup professionals