I'd suggest a three way fix.
1. Epoxy along the crack and then warm it with a hot air gun, it will go runny and soak in. (Or us low viscosity cyanoacrylate).Do this on back and belly.
2. Clean up where the knot was with a dill or round file to sound wood and epoxy in a snug fitting fine grained Yew plug. Once it's had 24 hours to set saw and file it flush. The point of this is to remove the notch which is a focus for stress. Filling it also allows you to work that edge evenly without your tools snagging.
3. A linnen thread binding around the limb just beneath the knot with epoxy massaged into the binding (Or sinew and hide glue/TBIII)
I think it will be fine if you do all three.
A fancy fix would be:- do 1, and 2, but then rasp out a nice long flat slice of sapwood from the back at and angle so you go right down to heartwood along the edge of the bow and it feathers out to nothing by the centre of the bow.
It must cover the whole length of the crack plus a good half inch or so either end. Glue over a long patch of sapwood and then carefully blend it in. Gotta use a decent bow making glue or Araldite precision would do it.
Obviously there are no garantees, but laminated bows hold together ok, and you are just laminating in a small section.
Del