Currently I don't manage many people, I mostly manage myself and do most of the dev work on my own. For example in the past three days, I've spent 70% of my time in either GIS or Python applications.
But I am definitely not super attached to that kind of work - if anyone else can do it, I'm fine with them doing it, as long as it's up to par. Part of this transition is (hopefully) moving closer to a role where I figure out and get to play with technology and datasets, and then surrounding myself with people who are much more eager and qualified to do the legwork.
My attitude towards him leaving is mostly that I embrace panta rhei, that the only constant is change. In my 18 months here I've seen my company grow by two dozen people and lose almost a dozen, on a company size that is now in the eighties. I'm happy for him, he seemed to be struggling to find his place for the past year. Wasn't that attached to him, but I do think I'll miss him.