he not express - subjunctive ?

[Abstract Idea]

"It is important that he not express critical feelings about the letter. Sharing letters needs to be a safe time." (Extracted from "Men are from Mars, women are from Venus", by John Gray)

Usually I would expect to read "he does not express" here. Is this the famous "subjunctive modus" again? I need to be sure about it. I have been studying and teaching English as a second language for some time but I have never seen an ESL book address this subject.

By the way, next time I get caught by forgetting a 3rd person final "s" in my writings, I will simply say: "Oh, it is the subjunctive modus, don't you know?"

[TheParser]

(NOT a teacher): INDICATIVE (a fact)/ SUBJUNCTIVE (a wish in speaker's mind). (1)Tom: Mona expresses her opinions too much. I'm going to tell her to stop. You: Don't do that. It is important that she expresses her opinions. It's good for her mental health. (2) Tom: Mona never expresses her opinions. I'm going to tell her to start talking more. You: Don't do that. It's important that she does not express her opinions. She does not want to offend anyone. (3) Tom: Mona never expresses her opinions. I think she should. You: You're right. She is too quiet. She is keeping her feelings pent up. I agree that it is important that she EXPRESS her opinions more. (I hope she will, but who knows.) (3) Tom: Mona says that she plans to express her opinion about the secret we three share. You: Oh, no! It is important/It is my wish/ It is my demand that she NOT EXPRESS her opinion. If she does, all three of us will be in big trouble.

[Abstract Idea]

(NOT a teacher): INDICATIVE (a fact)/ SUBJUNCTIVE (a wish in speaker's mind). (1)Tom: Mona expresses her opinions too much. I'm going to tell her to stop. You: Don't do that. It is important that she expresses her opinions. It's good for her mental health. (2) Tom: Mona never expresses her opinions. I'm going to tell her to start talking more. You: Don't do that. It's important that she does not express her opinions. She does not want to offend anyone. (3) Tom: Mona never expresses her opinions. I think she should. You: You're right. She is too quiet. She is keeping her feelings pent up. I agree that it is important that she EXPRESS her opinions more. (I hope she will, but who knows.) (3) Tom: Mona says that she plans to express her opinion about the secret we three share. You: Oh, no! It is important/It is my wish/ It is my demand that she NOT EXPRESS her opinion. If she does, all three of us will be in big trouble.

Thanks Parser, your nice examples did clarify the point to me.