Is 医好了 outdated in favour of 治好了?
医好了, to me, is more often used in old times, that's why it's totally ok to say that in HongKong, considering HK is still using traditional Chinese. In modern Chinese, 治好了 is more natural, but in some formal occasion we can use 医 and 治 together as one verb, i.e. 医治

examples:

张医生医好了无数病人。(it's ok, but less used in daily communication, I would use it in a composition, or in HK maybe? I don't know since I didn't go there)

张医生医治了无数病人。(sounds formal, I would use it in a report)

张医生治好了无数病人。(sounds more familiar and nature, I use it in my daily life)