Burglars struck at the house in Wolverhampton on July 10 while family and friends paid their respects to the four-week-old baby boy, who had died in his sleep on Father's Day.
The boy's grandfather, who has asked to remain anonymous along with the parents, said the family found the house had been turned upside down when they returned from the temple.
Jewellery, money, watches and a ring were taken in the raid in Fourth Avenue, Low Hill.
Now family friend Conrad Brissett has set up a fundraising page for the family which has raised more than £600.
Mr Brissett says on the page: "I'm raising money for a grieving family who not only had to suffer the awful sudden death of their four-week-old baby boy, but during the funeral which I also attended, they came back to their house, only to find their entire home ransacked by heartless burglars, who clearly knew that the funeral of a little baby was not only happening, but used that for their own horrific means.
"To say that they are in a place of pain is an understatement, and their faith in everything is at an all time low.
"This is more of a gesture just to let them know that they are not alone, there are good people out there, and to be united in their grief, and in the wish to get some kind of comfort in this awful situation.
"Anything given will be greatly appreciated guys."
To read more, or to donate, visit gofundme.com/f/help-for-family-with-baby-loss-and-a-robbery
West Midlands Police said no arrests have been made and enquiries are ongoing.
Anyone with information is asked to contact police via Live Chat at west-midlands.police.uk 8am - midnight or call 101 anytime.
Crimestoppers can be called anonymously on 0800 555 111. Quote crime reference 20WV/160633P/20.