Should Catholics attend parties celebrating the dead?
The short answer
No Church document forbids it. Going may help honor a friend's last wishes; if the atmosphere seems inappropriate, offer your sympathy and leave quietly. You may also have Masses said for the deceased.
No Church document is known to prohibit attending. Going might let your husband feel he has honored his friend's final wishes.
If the party atmosphere seems inappropriate, you can offer your sympathy to the bereaved and quietly leave. You might also have Masses offered for the repose of the deceased's soul.