I've checked out the St. Louis City directories:
1891 (year ending 1 Apr 1892):
Albert Ilbry, photographer, 1426 Franklin av.
he doesn't appear in the 1892-1897 directories when Emma reappears:
1897 (year ending 1 Apr 1898)
Emma Ilbery, wid Albert, r 1623 S 9th
She is not in the 1898 directory
She shows up again in the 1901 (ending 1 Apr 1902) directory:
Emma Ilbery, wid Albert, r 1426 Dolman
1902 directory:
Alfred and Emma, 1623 S 9th
This sort of leads to your assumtion he may have died in Illinois, since Emma doesn't reappear in Missouri until the 1897 directory. Either that, or he died prior to 2 Apr 1892 and Emma moved to Illinois.
His father and mother were still in Missouri, and by this time, William was residing in Memorial Home. In the 1899 directory, both Susan and William are residing in Memorial Home.