I guess it could be sick asylum, but as Edward was born in Limehouse I would have thought Ratcliffe is where he would be placed.
This family have lead me a merry dance.
Elizabeth Louise Brown married Edward Joiner 16/9/1894 - Bromley
She 23 and he 25
They have the following children
Elizabeth 1895 - 1896
Edward 1896 - 1960
Matilda Ann 1898 -1973
Alfred William 1901 - 1974
Emily Martha 1903 - 1906
William Henry 1905 - ?
Richard 1907 - 1911? (the only death I can find but in Greenwich)
Robert 1909 - 1967
1901 census Limehouse RG13/322/37/20 as Joyner
1911 census Grenade St. Limehouse RG14 PN1568 SN147 which has some oddities, both Elizabeth and Edward's ages are wrong, Richard is transcribed as 14 when it should be 4. She claims 5 live births, 2 deaths. So the 3 children in Board schools she has not included, perhaps. The census is 'signed' Mrs Joiner - Elizabeth made her mark when she married.
It appears the children were placed in schools, as some of the workhous entries say from *** school. In 1908 William Henry was admitted for rheumatism and Heart disease (although he joined the army in 1928, and I cannot find him again after this)
Alfred William in 1907 was put in the workhouse (infirmary, I suspect) with whooping cough from a school in Swanley.
I have never found a death for Edward b1868c - he is recorded as deceased when Matilda marries in 1927 and when William joins the army in 1928 gives his mother as his NOK - Elizabeth is my line, so I have not delved into his past, but it looks like he too spent time in the asylum as a child, so perhaps you are right he was a sickly soul.