And dozens of others reporting the same

The media, Biden and etc called it a funeral, It was not an actual funeral.
Sicknick was ‘lying in State or in Honor’ where all came to pay their respects.

“Lying in State or in Honor
The U.S. Capitol has been considered the most suitable place for the nation to pay final tribute to its most eminent citizens by having their remains lay in state (in the case of government officials and military officers) or in honor (in the case of private citizens).”

“Lying in state is the rare honor granted by the United States to a deceased official whose remains are placed in the rotunda of the United States Capitol in Washington, D.C., for public viewing.”

aoc.gov - Lying in state honor

Sicknick remains were taken to Arlington Cemetery where a ceremony took place, it was closed to the public. I cannot find any information Biden attended so I am assuming Biden did not attend
the ceremony at Arlington Cemetary.