Can psyllium husk be used as gelatin for jello?
Psyllium husk is a good source of soluble fiber, but it's not a very good stabilizer or a gelling agent.

If you want to replace gelatin inn recipes there's plenty of great vegan substitutes. I'd recommend using agar-agar instead; it's the closest gelling agent but it's stronger, so you need to use less than you're used to.