Yeah confirmed. The donor card is considered a collection of crates, when you collect it you collect all the weapons in it as if they were crates. When the donor card gets blown up, it's the crates inside it that blow, not the donor itself, that one does 0 damage. When there's only 1 weapon in it (which is necessary, otherwise no donor emerges), it does the same damage as 1 weapon crate. Whereas 3 weapons inside a donor does 3x as much damage (but with the blastzone of a single crate).
In your game the dude must have picked up quite an arsenal. Perhaps even 8 or 9 crates. When that blows you get the same kind of explosion as you get when you pile a whole stack of mines together.
I didn't watch the whole 28 minute replay though, so I can't tell how many he picked up.