I'm pretty sure he's one of their seminarians. Maybe Martin can confirm that. He was in the position of sub deacon. However, not being ordained to the sub diaconate he was what's called a "straw sub deacon." When a situation occurs when there's not enough clergy to fill those rolls, any cleric can fill in for that position. I think the sub diaconate is the highest position you can do that with. I'm pretty sure that is the case here but maybe perhaps one with more knowledge on the liturgy can confirm or dismiss what I've said.
You're right about the "straw subdeacon".
However, the black seminarian isn't even a cleric -- who would have conferred the tonsure (which is how clerics are made)?
Speaking of seminary jargon, we had another slang term at the Winona seminary -- a "coat hanger". That was a First Year seminarian. Why call them coat hangers? Because A) they got to wear the cassock full time, but B) they didn't have any "right" to wear the cassock -- just like a coat hanger. On Feb 2nd of their 2nd year, when they became clerics, THEN they gained the right to wear clerical attire (including the cassock).
As far as I know, every "seminarian" at the Boston "seminary" is a glorified coat hanger. They can dress up like priests like people dress up as Saints for halloween. But they have no more "right" to wear the cassock than I do, because they haven't been tonsured.
God bless the Boston fathers for saying a funeral Mass for the dear Faithful departed (maybe God will grant them the grace of conversion for their good deed!), but let's not forget what a disaster the Boston, KY "seminary" is. Fr. Pfeiffer -- and yes, even the beloved Fr. Hewko -- are waging WW3 against Bishop Williamson and the other 2 Resistance bishops. They call them "fake Resistance" and slander them unceasingly. They also attack countless confreres in the Resistance, and the only TRUE reason they do so is because the priests in question won't submit to the authority (papacy?) of Fr. Pfeiffer.
That is why, despite the handful of good deeds they do, I must end by dismissing Fr. Pfeiffer/Hewko and their operation. They are agents of division and sectarianism.
For the past couple years, the good they do has been surpassed by the evils they do.