Learn Turkish: Uyanmadan gerçekçi rüyalar görecek. - He will have realistic dreams without waking up.

It combines the verb root uyan- (to wake up) with the suffix -madan. This suffix means "without doing" the action. Because uyan has back vowels (u, a), we use -madan instead of -meden to follow vowel harmony.

Why does the sentence use görecek (will see) instead of a verb for "will have"?

In English you "have" a dream, but in Turkish you "see" a dream. The set phrase is rüya görmek (to see a dream). Here, gör- (to see) takes the future tense suffix -ecek, meaning "he will see (dreams)".

What is the -çi at the end of gerçekçi doing?

Gerçek means "real" or "truth". The suffix -çi is an attachment that often creates a word for an occupation, an enthusiast, or a personal trait. Here, it turns the base word into the adjective "realistic".

Where is the word for "he" in this sentence?

It is hidden in the verb. The verb görecek ends with just the future tense suffix -ecek. Because there is no extra personal suffix at the very end, it automatically means the subject is "he", "she", or "it" (the third person singular form).