There is someone saying that there are only two (obligatory) daily prayers, not five, and that there is no special prayer on Friday? Can we declare him a disbeliever?

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.

Allaah The Almighty made it obligatory for His slaves to perfrom  five prayers per day. There is a consensus of opinion among Muslim scholars over this point. This point is known by both knowledgeable and ignorant people. Moreover, this point is supported by the Sunnah.

If a person denies that Allaah The Almighty has made it obligatory on His slaves to pray five times a day, then he would be considered an apostate. In this case, for three days the Imaam (the Muslim ruler) or his representative must ask him to repent due to what he has said. If he does not repent then the penalty of apostasy is death.

Only the Imaam or his representative can implement the prescribed punishments. Other individuals are not allowed to execute the prescribed punishments. 

Allaah Knows best.