Asalam-o- Alaikum
A person(born in Muslim family) gets into severe depression and remains in the miserable situation for almost 2 years. He becomes doubtful with reagard to existence of Allah during that period and leaves the prayers entirely however did manage Ramadan and most friday prayers with the doubtful iman. Later on(at the end of those 2 years) he recieves guidance from Allah and Alhamdulilah his iman restores and His life once again becomes beautiful.
the question about whether he has to pray for all the lost prayers in those 2 years given that in those 2 years his physical and mental state was not usually normal due to severe depression but now he his perfectly normal and is in Alhamdulilah excellent state.
kindly take into account lost prayers preceding
before these two years when person was normal.
what about fasting of ramadan in those two years, will they be accepted sicne he managed all of them even though his state was not good.
Jazak Allah

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

Having doubts about the existence of Allaah The Almighty is foolishness and an act of disbelief that takes one out of the fold of Islam. Whoever harbors doubts about the existence of Allaah The Exalted is a disbeliever, and it is known that prayer, fasting and any other good deeds of the disbeliever (whether an originally disbeliever or an apostate) are not accepted, as Allaah The Almighty said (what means):

·     {The example of those who disbelieve in their Lord is [that] their deeds are like ashes which the wind blows forcefully on a stormy day; they are unable [to keep] from what they earned a [single] thing. That is what is extreme error.}[Quran 14:18]

·     {And what prevents their expenditures from being accepted from them but that they have disbelieved in Allaah and in His Messenger and that they come not to prayer except while they are lazy and that they do not spend except while they are unwilling.}[Quran 9:54]

However, when the disbeliever embraces Islam and believes in the existence of Allaah The Almighty with certainty, he does not have to make up for the missed prayers.

Dear brother, you should know that doubts about the existence of Allaah The Almighty are of two types:

1-  Mere devilish whispering with the Faith firmly-established in one’s heart. In such a case, one has to resist this whispering seeking refuge with Allaah The Almighty and refrain from speaking about them.

2-  Firmly-established doubts (not mere thoughts), according to which one speaks or acts and this is disbelief in Allaah The Exalted.

Subsequently, if you belong to the first type, then you are a believer, as Abu Hurayrah reported, that some people from amongst the companions of the Prophet came to him and said, "Verily we perceive in our minds what everyone of us considers too grave to express." He said, "Do you really perceive it?" They said: "Yes." Upon this, he remarked, "That is the manifest faith." [Muslim] In such a case, you have to make up for the missed prayers as clarified in Fatwa 83727, and your previous fasting is valid.

However, if your doubts belong to the second type, then, you do not have to make up for the missed prayers and your previous fasting is invalid.‎