Help with dye

My mums has a top that has changed colour in the sun. Its 100% polyester. I dont know much about dyes but I know natural fibres dye well and fake fabrics dont. Is there a special kind of dye I can use for polyester fabric.
Ta

I’ve used iDye poly a couple of times, massive failure the first time. You have to use the stovetop for the poly dyes and I didn’t use a pot anywhere near big enough that first time but it worked well the second time. Just make sure you use a pot with plenty of room for the fabric to move about in and keep it moving, stirring and shifting it about in the dye very often and it should be fine.

I think you can use Dylon for synthetics - the colours may not be as strong as for natural fabrics, but I think they can be used. Check on the packets.

ETA: Actually, I think polyester on its own doesn’t dye well - poly/cotton will, but not 100% polyester