Does the visionary still deserve the glad tidings he received in a dream from two noble prophets, after what befell him of heedlessness and turning away from righteous deeds?

Interpreting dreams is not within our specialization. Seeing the Prophet (peace be upon him) in a dream in his true form is good, for he (peace be upon him) said: "Whoever sees me in a dream has truly seen me, for Satan cannot impersonate me." If the dream is good, it is from Allah, so one should praise Allah for it and speak of it. If it is bad, one should seek refuge in Allah from its evil and not mention it to anyone. A Muslim should strive for uprightness in acts of obedience, for what matters is how one's life concludes, as the Prophet (peace be upon him) said: "Deeds are judged by their conclusions."