I am heartbroken and so sorry for his girls; may they find the emotional support that they need now and in the future.
The devastated, haunting looks on his daughter's faces will be unforgettable. The sisters will need not only emotional support but counseling too - they need to know this was not in any way their fault. It's also becoming apparent that depression can run in families - so they need to be aware of the signs and symptoms in their own selves, and to seek help if needed.
The family has handled this wonderfully thus far, in the best possible way.
Depression can be so deep and overwhelming that no matter the support, love and help received, the person cannot see their way out of that pit. Ari must have been in just such a place.
Peace, love and comfort to them all.
Edited to add - I do hope, after a suitable period, Maud will publish the children's book she wrote with her father. It would be lasting memorial, and any proceeds could be given to a charity that helps those who suffer from depression.