Is it obligatory to make up missed prayers, and is expiation due for numerous oaths broken during a period of not observing prayer?

As for abandoning prayer after puberty: If it is out of denial, then it is disbelief by consensus, and there is no make-up prayer required for an apostate according to the preponderant opinion. If it is due to laziness, then there is a difference of opinion as to whether it is disbelief or not. If it is considered disbelief, then there is no make-up prayer required for him according to the preponderant opinion. If it is not considered disbelief, then the majority holds that making up the prayers is obligatory, and adhering to this is more appropriate to avoid disagreement.

As for breaking an oath: Whoever does not consider abandoning prayer to be disbelief, then expiation is required of him. As for whoever considers it disbelief, there is a difference of opinion on the matter.