Commenting on the Shulchan Aruch in siman 289 which states that one may not taste anything before kiddush shabbos morning, except water, the Biur Halacha s.v. Chovas Kiddush writes that that it is simple that whoever has a hetter to eat before prayers, such as one who is eating for refuah, such as mentioned in siman 89 siff 3, must make kidush first.
In siman 89 #22 brings various circumstances and details whether one can drink coffee before prayers are brought up. The Mishna Berurah ends the discussion by giving his hetter for someone to coffee for refuah. This is obviously not using a 'coffee is only water' hetter as the Shulchan Aruch there allowed water as well. The hetter for water is that it is not haughty to drink it before praying. Coffee, as mentioned, needed the logic of refuah to be allowed.
So, does this person need to make kiddush before he drinks his coffee? It would seem he does, but as far as I know, nobody makes kiddush before having a cup of coffee shabbos morning before shul.