Hello. Don't bother with the Theodore Jacobus who died in NYC in 1946. I found his obituary, he was a physician married to Therese Badenheimer. The 1900 and 1905 census shows us that his parents were Herman and Minna Jacobus.
Your Theodore Jacobus and his father Nathan (both metal dealers) were in Hoboken, NJ in the 1900 census.
If you care to have them, I found the obituary of brother William Jacobus (metal dealer) and a news item with his photo. If so, email address please.