You chose a good yeast for high alcohol. I am not sure what caused the stress, but keep it under airlock for now. Is there any sign of fermentation, i.e. bubbling in the airlock? I would take it one step at a time. Finish the fermentation and then if there is still the H2S smell, address that by one or a combination of the following: stirring, splash racking or introducing copper in some form to take up the sulfur. Then you could proceed to stabilizing, clearing and back-sweetening.