I would guess MIPS helmets might possibly help with ice skating falls, in the sense of the slip plane redirecting the energy from angular and rotational impacts -- not that skaters are going to be wearing helmets, as someone already pointed out. And to think about what wearing a helmet would do to one's balance, and especially making one top heavy with a huge head - how to jump, be lifted, execute footwork with a helmet sized, unnaturally heavy head! But there is interesting safety technology out there -- also the inflatable helmets, now that I think about it. Anyway, MIPS helmets are increasingly used in equestrian sports, where falling from a horse jumping and/or galloping at speed can send riders head first into the ground at high velocity.TBH a helmet won't prevent this type of TBI. It's the sudden stop that causes an injury as the brain is still moving inside the skull and is bruised when it impacts the bone. A helmet won't stop that from happening. It can often prevent a skull fracture. If the brain is only bruised, it's typically a concussion. If parts of the brain is torn (I won't go into details for those who don't want to know), damage can be different. In either event, it's traumatic and I hope she recovers quickly. And, I feel for the partner as well.
Sorry for the tangent. Glad to hear of the excellent prognosis!