A Grundig Satellit will NOT hear the same things an Icom/Yaesu/Kenwood/etc... HF radio will. You will get the powerful nutball shortwave religious broadcasters just fine with the Grundig. To get the HF aircraft and military stuff you really need a decent HF rig.
Mancow, he has a Grundig 750 which is a massive portable. It has way more of a front-end than say a tiny Grundig G3 portable. The radio has a BNC input for an external antenna. This means that it can accept most external antennas safely. As always with these "desktop" portables, there are no guarantees.
Yes, a HF receiver is highly recommended for any serious monitoring but it sounds like he isn't ready to make that kind of commitment.
A *quality* active loop would be a safe investment; however, they are not cheap. That being said, they are very worth the cost and (presuming it's installed correctly) will drastically enhance any shortwave listening.
Ridgescan, E-Man, Solarix, myself, and plenty of others can attest to the difference of the active loop compared to a wire antenna.