I am in the midst of rereading the Thousandfold Thought and came across this other mention of Proyas mother.
It is Chapter 4 (kind of a weird chapter since it includes the emperor being killed by his mother, the orphan Hertata being taken by slavers in Summa [what the hell was that about]). DA is reflecting on how things have changed since Kellhus has taken over the Holy War and remarks
"On one occasion, after Esmenet's palfrey was lamed while descending a precarious switchback trail in the Enathpanean hills, Achamian watched as some dozen knights offered to give her their chargers - something tantamount to giving her their honour, since their mounts were their means of waging war. Achamian had witnessed much the same while accompanying Proyas and his mother to her dowager estates in Anplei."