In the Mexican state of Puebla, people refer to ripen foods as "cocidxs". "El aguacate ya está muy cocido", "The avocado is already very cooked", meaning "very ripen". It was nice to find in Romanian the same meaning.
Is 'proaspete' not a good alternative for 'coapte'?
No. Proaspăt means "fresh". You may have something "fresh" but not "ripe".
Is this passiv form?
No. The passive voice form of this sentence would be "Two ripe peaches were offered by him." (Not sure what that would look like in Romanian.)