This may be a Stupid question, and since I am new to brewing beer I might have some more of these questions coming in later. My wife for some reason bought Brewer yeast, I am curious if this can be used as the yeast in beer brewing? forgive my lack of brewing terminology.
The simple answer is "maybe". If it has not been heat treated or otherwise sterilised, it may be used to brew. However "nutritional supplements" are often sterilised so it may be difficult to tell unless clearly stated. Even when not sterilised, if it is old stock it may not be sufficiently active to form a vigorous starter culture. Try some out by mixing/shaking in a clear jar/bottle with some sugar and some tepid/warm water. If the stuff is foaming well after a few hours then it probably could be used to brew. Whether that is a useful thing would depend on the beer being planned. For example "brewers yeast"if active may not be lager yeast....
For the sake of a few dollars it may be best to get some fresh brewing yeast of a strain suitable for brewing the desire beer. A "fresh" packet of dried yeast should last a year or so when kept cool in the fridge perhaps less on the shop shelf. Liquid ("smack") packs and culture tubes are fashionable but may not be any more advantageous to the novice brewer.
I would prefered to write a comment, however i have not enought reputation yet.
As has been said, that yeast is dead, so it will not ferment.
On the other hand, some people around internet talks about using this dead yeast as yeast nutrient (example). However some say it could add unwanted flavours due to the autolisys (no idea about the theory at this point).
In my experience, I have tryed it adding a spoon into the boil. Do not detected neither, bad flavour or better fermentation.