"His plate is close."
Translation:הצלחת שלו קרובה.
there is no such thing as masculine or feminine sentence, in a single sentence there could be both feminine and masculine words. there is construct state in this sentence, the word "צלחת" is nomen regens, and the word "קרובה" is nomen rectum, since the word "צלחת" is a feminine word the closeness of the plate must be expressed in the feminine form of "קירבה" (closeness), which is - קרובה. if you'd wanted to relate to the person's closeness to a plate (or even his plate) you would say "הוא קרוב לצלחת" (a plate) or "הוא קרוב לצלחת שלו" (his plate)