A twisted ankle is usually an ankle sprain and it really all depends how bad it is. If he's still in pain or its still swollen after a couple of days, then it's worth getting it checked out by a physio to assess how bad the damage is (hether the ligaments are just stretched, whether they're torn etc.). The immediate treatment is ALWAYS protection first, rest for first few days, ice it up - 20 mins at a time to reduce swelling, compression (elastic bandage or similar) and, when resting, elevate it above heart level. A good quality ankle brace would be a good idea to support it but unless it's very bad, your husband should be able to move around reasonably freely within a couple of weeks - it all depends on how active the holiday was planned to be. If you were hiking, then I'd rule it out - if its beaching and sightseeing, then fine with care. Speak to your physio for assessment and advice and then make your decision - holiday insurance will pay out for cancellation if you have doctors advice against travel.
Frankie McAllister ● 4304d