Is the fasting of one who does not pray, or one who prays in Ramadan and abandons prayer thereafter, accepted?

One of the greatest calamities is abandoning prayer (Salah), as it is the pillar of faith and the differentiator between disbelief and belief. The Prophet, peace and blessings be upon him, said: "Indeed, between a man and disbelief or shirk (polytheism) is the abandonment of prayer," and "The covenant between us and them is prayer; whoever abandons it has disbelieved." The Companions of the Prophet, peace and blessings be upon him, held the view that one who abandons prayer is a disbeliever. Scholars differed concerning one who abandons prayer out of negligence: The Hanafis believe that he does not disbelieve and should be imprisoned until he prays. The Malikis and Shafi'is believe that he does not disbelieve but should be executed as a legal punishment (Hadd) if he does not repent and pray. However, the well-known position in the Hanbali school of thought is that he disbelieves and should be executed as an apostate. This leads to a difference in the ruling on the fasting of one who abandons prayer; those who do not consider him a disbeliever deem his fast valid, while those who consider him a disbeliever hold that his deeds are null and his fasting will not benefit him. Therefore, one must be diligent in prayer.