1)
It is written "Im", but we do not pronounce it!
1.
Torah Temimah citing Nedarim 37b. This is a tradition from Sinai.
2.
Rashi: "Im" implies Safek. There is surely a closer Go'el! Salmon (Bo'az' father), Elimelech and Tov 1 were brothers. Bo'az said "our brother Elimelech" (4:3) - a man can call his uncle 'brother' (Rus Rabah 6:3). "Va'Yishma Avraham Ki Nishba Achiv" (Bereishis 14:14) - he was Lot's uncle [and the verse calls him his brother]. Bo'az was a relative of Machlon and Elimelech (first cousin and nephew, respectively), but Tov was closer (uncle and brother).
1
Verse 13 implies that Tov is the closer Go'el. Pesikta Zutresa 4:1 explicitly says that he is Ploni Almoni. (PF)
