Could also be that he was offered help in looking for better employment (if you assume that panel 2 is about Hitoshi asking if being a mere artist is good enough).
Also: When I went to check out the pixiv source, I noticed that he has an ad up for what he's bringing to Comiket... and it does include Kogasa mugs (as seen previously in the strip) for 1000 yen. They look really cute... Kogasa-girl on one side, Kogasa-umbrella on the other.
BadRoad said: Destroy the world?! But that's where Kogasa keeps all her stuff!
+1 For references (... spoon!)
Anyway, I think it could have been money, or a perhaps a job offering, or I have a bit of an idea from the last few strips that maybe it was an offer of something they could make a romantic getaway in...
Okay, so it's been 3 years and I'm still wondering what Kanako!father was actually going to give as a gift. Artist commentary doesn't seem to mention anything...
The Power of ScienceWell, all kidding aside......we have no problem with you two getting married!Nothing wrong with that, is there?I know—how'd you like the power of the Yatagarasu as an engagement gift?No, thank you.You don't mind me being an umbrella youkai?Please, give that to the underground raven.Aw, but it's got the power to destroy the world!What are you trying to get me to do, Dad-in-law!?