Any idea what can cause slight shaking and a fever?

The flu?

When I was super anemic I sometimes had an slightly elevated body temperature and was shaky, apparently that’s not normal for it though, as you’re supposed to have a decrease in temperature. He should check with his doctor while he has the symptoms.

It’s only a slight fever. Hes not burning up

There are tons of things that can cause that. Anything from not worrying at all to immensely worrying. It’s most likely it is a cold or flu issue.

Edited to add: If he’s taken anything for the fever, that could cause the shakes depending on what it is. Some cold/flu meds make me shake. If that’s what it is, talk to the doc. In me, it wasn’t an issue, but it was disconcerting, so I switched to a different med.

I am not a doctor, don’t take my advice. But this used to happen to me whenever I let my core body temperature drop. I didn’t realize at first, I was doing it, but I would let my clothes get wet walking in the rain and say “oh they’ll dry eventually”. And then hours later that night, I’d start shaking uncontrollable. I eventually worked out I couldn’t get my temp up with clothes or blankets, but a hot water bottle would heat me up quickly and I’d feel a lot better.

in my experience, those symptoms might be caused by a kidney stone/ urinary tract infection. Should see a doctor, pronto.