Gabe's infirmity plays several roles in the play, but two seem to resonate with me the most. The first is that Gabe gave his life and service to the nation during the war, only to return a shell of his former self and unreachable to anyone as a result. Whether or not he intended to do so, Wilson is making a social statement about war, especially those people of color who gave their services for a nation that was unwilling to reciprocate in terms of civil and social recognition. In addition to this, Troy, unable to reach his brother, uses the money from Gabriel's disability to build his house. This is another role Gabe plays in the drama.
In a larger sense, Gabe's symbolic meaning seems to be very evident in the play. He believes to be the Archangel Gabriel. Ironically enough, this figure of salvation, as Gabriel represents the messenger of God. The playing of his trumpet represents the end of time, and the moment where the final judgment lies. It is important to note two things bearing this understanding: 1) No character in the play sees, or truly authenticates, that Gabriel, the character, is actually Gabriel, the archangel. This means, that the figure to note salvation is largely ignored. 2) When he does play his horn at the end of the play at Troy's funeral, the mouthpiece breaks, and the horn is not sounded. The final judgment, suspended. The entire play seems to revolve around the notion of suspended relationships and associations. There is not a sense of closure nor finality within the play. This theme is evident with Gabriel, who sings, screams, and dances at the end of the play. We are left with an Archangel whose effectiveness is not realized, purpose not met, direction not given. Again, whether Wilson or not intended this, the result is evident, proving Gabriel's significance to the drama.