Translation:Aamir does not eat on Monday and Thursday.
In English, "and" and "or" are interchangeable in negative sentences. "I don't like pizza or beer" means "I don't like pizza and beer." Both are correct, but I think "or" is more natural in negative sentences in particular. This comment also applies to Julia (?) who doesn't go to Delhi in January or February—which means January and February. Basically, in English, "or" can mean "and."
I feel like in English it's very context dependent. I could easily say something like "you don't like pizza or beer?" And mean that I think you dislike one of them, and i why want to know which. On the other hand " I don't like pizza and beer" could mean that I like them both, but only individually.
Not a mnemonic, but this very interesting Wikipedia page explains their origins. (All the world's languages are here so you have to scroll down a bit to find the South Asia section.)
I made up a few really crude ones. :D In सोमवार the Som is a similar start to Mon so I know that's Monday. I remember बुधवार after Buddhism: the middle day of the work-week = the Middle Way of the Buddha. गुरूवार is next so "Guru" comes after "Buddha". शनिवार starts with a श like शुक्रवार but continues with the same vowel structure (अ-इ-आ) as रविवार so it comes between them.
Fun fact: सोमवार comes from सोम which is old Hindi for moon, by using Greek astrology, similarly like the names of the day of the week in Latin languages (e.g. lunes is Monday in Spanish). गुरुवार comes from गुरु, meaning teacher, because the god Jupiter was a teacher in Hindi methology. (Thursday is jueves in Spanish.)