As it says on the tin, Ferdinand of Austria dies youngish before he has a male heir, whilst Lajos II lives to "old" age with a large family (considering his sister's gaggle of kids and his bastard, Janos Llanthos' daughter having something like a dozen or more, apparently, I don't think this is unreasonable). How does this affect Europe (and the Habsburgs)'s future?
Well, there's a lot more to their fates than their progeny. Louis II died at the age of 20 at Mohacs, while Ferdinand lived to 61.
Since Ferdinand was not at Mohacs, he couldn't be killed there, so he must die some other way. He had a daughter born two months earlier; his eldest son was born eleven monts later.
So the double PoD is that Louis escapes the Mohacs disaster alive, while Ferdinand dies of some random infection at about the same date.
There are two major effects. First, Louis survives and continues to hold the crown of Hungary. This will constrain the actions of Sultan Suleiman, whose 1529 siege of Vienna was in large part a response to Ferdinand's 1527 invasion to enforce his claim to Hungary (Suleiman had recognized John Szapolya of Transylvania as King - as his vassal). If Louis lives, and Ferdinand dies, Szapolya makes no claim, obviously. so the struggle between Louis and Suleiman continues, but there is no Hapsburg intervention, and Hungary remains united - no "Eastern Kingdom of Hungary" under the Szapolyas.
Does Louis live to a ripe old age in exile? Or does he regain control of of all or part of Hungary? Does he make a deal with Suleiman?
The absence of conflict with the Ottomans will affect Charles' handling of the Reformation; he has more of a free hand. Also, however, he does not have his brother to take on some of the responsibilities.
And there will of course be butterflies: Charles may have no son or several, instead of one.