I wanted to ask about a Hadeeth in which the Prophet, sallallaahu alayhi wa sallam, said that the Hell-fire will not touch a person who sees me.
Another Hadeeth I read that a person who sees me in a dream will see me on doomsday and he will get the water from Houdh Kauser to drink. And Hell-fire will not touch him.
Now, if a person sees the prophet repeatedly in dreams is he worthy of getting the above mentioned blessings.

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 is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

It might be that you are referring to the narration reported by At-Tirmithi and which was narrated by Jaabir Ibn 'Abdullaah that the Prophet said: "The fire will not touch a Muslim who saw me or saw whoever has seen me." This narration is classified by Al-Albaani as weak. In addition to this, the same narration is reported by At-Tabaraani and narrated by 'Uqbah that the Prophet said: "A Muslim who saw me will not enter Hellfire, or a person who saw whoever has seen me, or has seen whoever saw another person who has seen me."  Even if this narration is authentic, what it refers to is the sight with one's own eyes as the narration suggests, but it does not refer to a dream. It is for this reason that some scholars said that this is peculiar to the companions and the generation that came after them. This is what Al-Mubaarak Poori confirmed in his book Tuhfatul-Ahwathi. However, a weak narration has been reported which suggests that the dream is included in it. Ibn 'Ady and Ibn 'Assaakir reported that Sa'eed Ibn Maysarah narrated that the Prophet said: "Whoever saw me in a dream will never enter Hellfire." However, some scholars classified this narration as weak.

As regards the narration you mentioned in your question that whoever saw the Prophet in a dream will see him on the Day of Judgement and that he will drink from Al-Kawthar river, it is reported by Al-Bukhari and Muslim but without the expression "on the Day of Judgement and that he will drink from Al-Kawthar river."

Allaah Knows best.