Learn Turkish: Allah size sıhhat nasip eyleye.

eyleye is formed using the 3rd person singular optative (subjunctive) suffix -e. In modern conversational Turkish, people typically use the 3rd person imperative -sIn (like eylesin or etsin) to express wishes for a third party. However, the older 3rd person optative -a / -e is still fully alive in traditional, religious, and formal blessings like this sentence.

Why use the verb eylemek instead of the much more common etmek?

eylemek is an older helper verb that means the exact same thing as etmek (to do / to make). While you wouldn't use it for everyday actions, it is standard to use eylemek in religious blessings, prayers, and poetic language. You will often hear it paired with words like nasip, yardım, or af.

What does nasip mean exactly in this context?

The noun nasip means "one's allotted portion in life" or "destiny." When paired with our helper verb to form nasip eylemek (or nasip etmek), it means "to grant" or "to destine something for someone." The sentence literally asks God to make health a part of your allotted destiny.

Why is the pronoun size in the dative case here?