It’s sad to have to cancel a trip for any reason. So much goes into the planning and the anticipation build up makes it so exciting. unfortunately, in this circumstance you are going to just have to do what needs to be done. Don’t for a second think that your poor FIL isn’t just feeling terrible about you missing the trip, being out of work and putting the workload on your DH and most of all…I am certain said procedure is scaring the crap out of him. Stay focused on him and helping him get better and get through this mess…disney isn’t going anywhere.