Considering his academic titles, what are the contribution of the automotive engineer, Professor Dr Dr h.c.mult. Hans List? What did he invent? I could not find anything except a brief obituary.
I think his honors are described in the bio you cite. He spent 50 years in academia, and as the title states,
The appellation "Dr Dr h.c.mult." shortens the Latin honoris causa multitudo - roughly "many honorary doctorates" - the first for his original Doctorate of Technical Science at Graz, the second for four other university honours.
If you need details on the specific university honors, I would suggest checking with the University of Graz, where he spent the majority of his academic career. Alternatively state university of Tongji, Woosung, in China
On the other hand, I'm willing to give him respect for being 100 years old and coming in to work the day before he died.