Gluten Free Challah not keeping shape
Spelt flour is not gluten-free. Light spelt flour has less protein (gluten is a protein) than regular spelt or strong bread flour, but it's still there (5-8% from what I've seen), so if you need gluten free you need to pick another ingredient. 

To answer your question, there are limitations to what you can do with low or gluten free doughs. Bread made with gluten is stretchy and keeps its shape because the gluten strands relax and become intertwined with each other, if you take the gluten out you lose that stretchiness and body. Dough improvers like xanthan gum can help give some stretchiness but not to the point of being able to make something like challah. Low or gluten free doughs are always going to be a bit crumbly - it's the nature of the beast - so my advice is to pick bread types where that's an asset.