German doesn't have a present progressive. Thats why the "präsenz" can be translated as simple present or present progressive. Used as present progressive, there is often a hint that something is happening right now:
"Er arbeitet grade" | He is working right now
"Er arbeitet im Moment| He is working at the moment
The present progressive form of low german, which is still standard in some dialects, is often used in casual language usage (Maybe because of the english influence).
Ich bin am Lesen. | I am reading
That is "sein + am + nominalized verb" (sometimes "beim" instead of "am")
Although it is used quite frequently, many people would consider it wrong.
I find this present progressive form in German quite interesting. I don't think it is because of English influence, this construction (pronoun + present of to be + extra word(s) + infinitive) actually also exists in other languages. It is mainly used to stress that it is happening at the moment.
"I am reading" would be
French: "Je suis en train de lire". Je + suis + en train de + lire
Dutch: "Ik ben aan het lezen". Ik + ben + aan het + lezen
Danish: "Jeg er ved at læse". Jeg + er + ved at + læse
Dutch is even a literal translation of German, since "am" is a contraction.
These aren't the same in English. He is working all day = he is at work now. Happening NOW. He works all day = this is his habit, what he usually does. May be happening now, perhaps not. (It could be late at night.) Any German speakers out there who can tell us how this is done in German?
What are you trying to say? "Ein Alltag" means "a weekday" or "a working day", and "alltags" is an adverb meaning either "on weekdays" or "every day". I don't see how any of these are applicable to the original sentence "he works the whole day". It does not imply that he works every day, it is just that on this particular occasion he spends the whole day working .