This looks like the death of their son, Henry, age 16, but there are no other Husses at findagrave.com in the cemetery or even the county
NJ Deaths & Burials
Henry Huss, died 18 May 1881, Newark NJ
born: England; residence: in state 7 years
https://www.familysearch.org/ark:/61903/1:1:FZKY-H3BHenry Huss
Birth 1864, England
Death 18 May 1881 (aged 16–17)
Newark, Essex County, New Jersey, USA
Burial Fairmount Cemetery, Newark, Essex County, New Jersey, USA
Memorial ID 187279341
notes at findagrave.com:
funeral services from St. Paul's Episcopal Church, Newark, Essex, NJ.
resided at 93 S. 6th St, Newark, Essex, NJ.
died aged 16 years.
buried 5/22/1881.
https://www.findagrave.com/memorial/187279341