"Don't give him too much pressure."
Current default English translation is not idiomatic and should be changed. Here's some more natural ways to say it:
- Don't put him under too much pressure
- Don't put him under too much stress
- Don't stress him out (colloquial and idiomatic)
- Don't pressure him too much
"Too big" is an adjective, and it goes before nouns.
I guess your expression probably comes from "Don't press him too much". Literally it would translated to 别压他太多. Unfortunately, this figurative meaning of "press" doesn't exist in Chinese. So it won't be easy for a native speaker to understand what you mean.
压力，别给他太大 is the only way I can think of to put it in front (it sounds weird without context)