Lupin | Snape
It happens. No one knows why or how. The tesseract gives memories to people of things that will happen to them in the future in their world. Sometimes it ages them to the age appropriate to those memories. Sometimes, as in Albus' case, it leaves their age as it was.
They are different types of werewolves to you therefore the effects of the potion on them are unknown. If they wish to try it then I would have to insist on contacting SHIELD to arrange for appropriate containment facilities as well as having medical staff on standby, just in case the side effects are unfortunate.