Why would he be called Kechewaishke Kechewaishke? He really only had one name (at a time). He was baptized Frederick so you could use that as a first name with his last name the same, as the Anishnawbe did in some cases.
BTW his father was On-daig-woes, aka Buffalo.
Siblings were sister, Pash-ta-comme-(go)-quai who married _____ Riel / Relle/ Rivet; and brother, Joseph Tchtchigwais who married Marie Tatchiga. That I know of.
I have a friend who may be descended from this person, I will let her know.