Well, in terms of the medically related law, they could have done this as lawyers without much difficulty. As mentioned 99.99% of all medmal, health law and other medically related area lawyers do not have an MD. Quite a few of my friends work in health law and didn't even take any health law classes in law school, let alone go to a med school. Nor do such lawyers ever need a medical degree. You hire nurses and doctors to review documents for you -- it's a cost you pass on to the client and you to some extent pass the liability for mistakes as well, so it's win win. You certainly won't earn any more with an MD than just having the JD if you plan to stay in law. So this isn't really a well thought out path. They may be trying to break into an area they haven't been able to, but it's a very low yield path -- they will spend 4+ years and $200k to end up doing something most folks will be doing right out of law school. In terms of academics, sure it can get you good credentials for that, but you will do it at a big loss in income/salary, so you'd better be sure you'll love it. But if academics is their motivation, great.
Bear in mind that the advice is a bit different if you already have the JD than if you haven't yet got one. To do the JD/MD you need to have a good notion of why you want both degrees because you will likely only be using one. If you already have the JD, which you got to practice law, and after having practiced, (or after a change of plans), you decide you want to transition into something non-law, and be a true career changer, then I get that, but you are basically going to forego using your prior credentials in most cases. So if you do one profession and later decide to change, they I understand having both credentials (not something you planned on at the outset, but hopefully no regrets). But if you are getting both from the onset, then you'd better have a well thought out plan because honestly few to no jobs exist which actually require that combo, and in most cases you could get to any job with either one or the other. You will thus need to convince an employer to create such a combo job, or just pick a field. Either way you will have a tough time recouping the investment of time and money it'll take to get both degrees, and will almost always be in a worse position than someone who got either/or degree and just starts working.
Only do medicine if you plan to practice medicine. Everything else has other higher yield paths.