Hmmmm...I don't know anything about those in specific. But the brown edges of the leaves looks like either over-watering or under-watering.Both can look pretty similar on the
plant itself. But if I were a betting man, I'd say the dead patches are a result of the former.
Hopefully someone else can add something more, but some ideas: Cut back the water, watch out for powdery mildew (in the pic, that white stuff on the edges of the soil has got me concerned) and other fungal issues, and ensure that the location has good air circulation. Treatment with a spray containing Copper Octonoate might also be prudent.
Hope that helps!