Despite his contentment, Collis returned for Ireland the
following year, helping Ireland claim a share of the 1926 Five
Nations alongside defending champions Scotland. With his
international rugby career over, his real career was just beginning
to take off. In 1932 he published a groundbreaking paper on
rheumatic fever and erythema nodosum, the same affliction that had
almost killed him, whilst a student at Yale.
On returning to Dublin, he set up the Irish Paediatric Club
(now- Irish Paediatric Association) and became its Honorary
Secretary. Outside of medicine, he set up the Citizens' Housing
Council, through which he campaigned energetically for a general
improvement in the provision of housing for the poor. He published
his autobiography, 'The Silver Fleece', in 1936.
Towards the end of the Second World War, Collis volunteered to
assist the Red Cross. As a result, he was one of the first people
into the liberated Bergen-Belsen Concentration Camp in northern
Germany. Having set up a children's hospital within the camp, he
became aware of just how many children had become orphaned whilst
trying to survive the camp.
He made it his mission to try and find homes for the children
and arranged the transfer a several of them to Fairy Hill Hospital
in Howth, County Dublin. With that done he adopted two more of the
children himself and returned with them to Ireland. He later wrote
of these experiences in his 1947 book 'Straight On' with co-author
and fellow rescue worker Han Hogerzeil, who later became his second
wife.
On his return to Dublin, Collis set up the National Cerebral
Palsy Clinic. This brought him into contact with writer and painter
Christy Brown. Cerebral palsy meant that Brown could write and
paint only with his left foot. In 1954 Collis contributed the
introduction to Brown's book 'My Left Foot'. The book quickly
became a best-seller and in 1989 was adapted to film, with the
actor Daniel Day-Lewis playing Brown.
The restless Collis and wife Hogerzeil moved to Nigeria in 1957
and, over the following ten years, helped set up the Institute of
Child Health in both Ibadan and Lagos. In 1973, now well past
retirement age, Collis moved to India to work in a leper colony in
Dichpalli, near Hyderabad. In addition to trialing new medications
for the treatment of children with leprosy, he encouraged them to
play cricket and joined in enthusiastically at the age of 73.
He continued to write up until his death in 1975, at the age of
75. He had two sons with first wife Phyllis, two more with Han, as
well as raising Holocaust survivor siblings Edit and Zoltan Zinn.
Zoltan Zinn-Collis wrote the book 'Final Witness: My Journey from
the Holocaust to Ireland' in 2006, recording his childhood rescue
from Bergen-Belsen at the hands of his adopted father.