PS4 profile primary for all games?

I wasn't sure what to call the question title. It is as follows: I currently have a normal Ps4 and have now bought a Ps4 Pro. I now plan to use the Ps4 Pro in the future and sell the normal Ps4 on classified ads or something. However, my little brother visits me for a week and since I have no pressure to sell my normal Ps4, he can use it for the week, after which I can sell it. Now to my concern. Since my PSN profile has all the games on it (I hardly have any CD games), how do I do that we can both access all games? Do I then have to keep my Acc as primary on the normal old PS4 so that my profile can access the games? How do I do that on my new Ps4 Pro? Do I add my PSN profile but don't set it as the primary profile or how does it work? So in the end he should be able to access the games from my profile with his own PSN profile on my old Ps4, while I can still play with my profile on the new Ps4 Pro. But the whole thing only for a week.

If he wants to use his profile, his must be primary. Then you always have to be connected to the Internet, which is usually. Eh shouldn't be a problem.

That means that he must have my profile (my profile has all the games in the library) on primary and can then access all games with his own profile and I have to be set to secondary with my profile and can then continue to play everything, right?

Yes