I can understand how the role lead him to discover it, but he can't have known before getting that role that they were going to put functionality in that infringed on his patent.
There's also been no evidence on either side (his part of theirs) to prove whether he did/didn't tell them in advance. It's completely plausible that after interviewing him and seeing his patent they became interested in adding that.
I personally think software shouldn't be patentable at all
http://www.binaryiris.com/node/26 so didn't even bother checking whether the patent is BS as the check is redundant
;)
My interest was more that everybody is judging both him and microsoft when their is insufficient evidence in the article to do so. It's entirely he said she said without the gender variety.