When I was teaching, we didn't have a choice about who had kids with learning issues, ADD, etc. That was because everyone had them, in a full inclusion model. The sped kids had support in the classroom with either a teacher or an assistant. We had a real co-teaching model. We did decide which kids would do better with which teachers/teams. It doesn't seem right or fair that some in your school get to opt out of having to learn how to address learning issues, like the person in question. Of course, this takes lots of collegiality, commitment, and modeling on the part of the administration. For quite a few years, I was on the looping team (6-7th). Our team was attached to the 2 classes for the more severely handicapped kids. Most had LA and math in their respective classrooms, at first. So, I didn't always have them in all 4 of my LA classes. But after a few years, they were put into my classes once they had a semester or 2 with the special ed teacher in LA. They came with an assistant, and in the case of the PDD kids, sometimes 1:1 assistants. The sped teacher did the exact same curriculum with her kids, on a modified basis, so we were always doing the same work. That way, when her kids came into my class, it wasn't a huge change. But, some of the LA teachers on the other teams, who had the more mildly handicapped kids thought I didn't have to deal with the same stresses they did. It wasn't true, I just had different stresses with the kids I had. As a former sped teacher, I always got my share. Usually, I got more than my share of the "gray area" kids, who never qualified for any services. Now that I know what I know, those were the kids that actually needed more help, in terms of social and emotional support.
Maybe this woman really does need to take a medical leave. And her partner needs to do her share of the grade level stuff!