Caring for a 90 year old husband recovering from hip surgery. How to encourage without being directive?

Can you not have a physical therapist come to your home several days a week to help him with his PT? People usually do better with PT, when it's not their family member telling them what to do. Also make sure he is taking his pain medicine shortly before any type of exercise, and put an ice pad on the hip area when he's done. Also maybe if can do the exercises with him, he may be more willing to go along. Good luck.

Was he admitted to a facility for rehab? Rehab will often work better than at home. He would be more compliant with pros than trying to recover at home.

Is the PT visiting the gentleman to support his exercise routine? Ideally this will be happening if the facility allows it; if not, perhaps the PT could provide some of the care team with moving and handling instructions so that members of staff can support the routine, working to a daily schedule. The key thing is for people in uniform to come in and lead the formal exercises so that the wife does not have to be involved.

The wife can then reinforce mobility by providing additional incentives for the gentleman to get up and move around. For example: do not take meals to him, serve them where he would normally eat (dining table, riser-recliner armchair, anywhere except bed!) and then allow plenty of time for him to get there. If there is a commode, and continence isn't a problem (you don't want him ever to have to rush), place it so that he is required to take a few steps and position himself before sitting down. If he can do without a commode during the day, support him to get to the bathroom at regular intervals. Never hurry him and never get into an argument with him about moving around: the aim is to make each mobilising attempt positive and worthwhile for him. Let trained people handle the therapy.

Try to help your husband to manage his pain.
Ask his PT about ice packs and meds and how often he should be getting up at this point in his recovery. He needs to be as pain free as possible in order to take the necessary exercise. I’m sure it’s upsetting for you to see him in pain. Encourage him to get up for the bathroom, to get dressed, to brush his teeth, bathe, take his meals, look out the window, whatever you can think of to get him to keep moving as is appropriate.
Little by little the moving will help him get better. It is hard work for him because no doubt it does hurt. I hope he is better soon.