I do not have a history degree, although I nearly acquired one as a second degree while obtaining my BS in one of the sciences.

So that's a disclaimer.

Anyhow, as there were no jobs in my chosen field I ended up going to law school and became a lawyer, which I have now been for over 27 years. There are a fair number of lawyers who have bachelors degrees in history, including two that I presently work with. A history degree, at one time, used to be considered a fairly good degree for somebody aspiring to be a lawyer and perhaps it still is (I haven't kept up on that).

Having said that, being a lawyer is a very hard line of work with an enormous career dissatisfaction rate and an attendant high rate of depression, alcoholism and other bad stuff. So I'm not saying I'm recommending it. I'm only noting it. It's now hard to find work as a lawyer in a lot of regions of the country and the field itself is consolidating meaning that the age old "solo" aspect of the profession is dying off or being relegated to minor stuff while the major work goes to larger and larger firms.

Usually somebody noting the field of law as an option is,in regards to your last question, obligated to go on about how lawyers (in litigation anyhow) research things, write, etc. etc., which is applying the skills a historian otherwise has. And that is true. However, given its nature only people who have a true, and very rare, "love of the law" (which again is quite rare) probably find it fulfilling. I'm not too certain that "fulfillment" in modern careers in general isn't a bit of social pablum at that. So, the probable answer used to be that people found work. Now that's more difficult.

And I'll also note, fwiw, that two lawyers I know who had history undergraduates are employed by academia in curative and history teaching roles, so I suppose there's some flow both ways.

Good luck to your brother, I wish him well.