From "What is the Sign of a healthy Person?" by Sri Swami Satchidananda: "The human body is a temple. keep it strong and supple."
Asana should be easeful. With Adaptive teachings (such as props and variations) we can make them easeful and accessible for every body.

Sutra 47, Book 2: Sthira Sukham Asanam = Asana is a steady, comfortable posture

The client wants to do a classic sun salutation. The long-term goal is to get him as close to that as possible within the limits of his body. The short-term goal is to use props and adaptations to complete a modified sun salutation as a starting point. The client will practice this, adjusting as he becomes stronger and more flexible.

Male, 55, lumbar spinal fusion (1983). Client has limited range of motion (especially in spinal flexion) due to the rods in his back. He reports becoming frustrated when attempting floor poses in a classic hatha class. He feels strong and capable in all lifestyle areas, and has no limitations imposed by his physician.

I envisioned watching the client moving through the traditional sun salutation (that is his goal to do), noting areas of struggle, and offering adaptations/alternatives/props. Ct would then practice with these adaptations until they became unnecessary due to improvements in strength and flexibility.
I would also offer other exercises and poses to support that process, based on my observations of where he might need more strength or flexibility.

I used asana from the hatha branch. The teachings, such as Sutra 47, Book 2: Sthira Sukham Asanam = Asana is a steady, comfortable posture, tell us that asana shouldn't be a struggle. In Adaptive TT we learned that asana can be adapted to anyone who wants to practice. We could do that with a change in position, or use of a prop to create more accessibility and more ease in the body and mind.

Ct did some gentle poses for warm up that suited his body, such as cat/cow, shoulder and wrist movements. We talked through a classing sun salutation and then practiced it. I practiced alongside, giving cues and offering props and alternatives as needed (eg. blocks under his hands to extend his reach/make more space in stepping back to lunge).
He has no trouble with the beginning poses and ending poses of the sequence, but says he has always struggled with stepping back to lunge, stepping back to down dog, and stepping back up to lunge and back up to forward fold.
As he locks flexibility in his spine due to the rods I was unsure that his body would allow that extent of movement, but I continued to offer adaptations and alternatives.
He is determined to do the entire sequence without a chair, but he is willing to use the blocks.
Ct tired quickly. (cont. below)

We looked at other poses that may extend his flexibility and strength to accomplish his goals: cat/cow (mobility), spinal balance (core strength), happy baby (hip flexion/flexibility), and shoulder stretches including down dog for more openness in that area.
Ct will practice these poses on his own and report back to me in a few weeks.

I applied the plan, but the short-term goal was not attainable as the modifications he was willing to use were not quite enough to do what I expected we might be able to do - complete the sun salutation, on the floor, with props.

I expected to offer other poses and exercises to enhance flexibility, mobility and strength - and I did. Ct was not ready to meet again by the time this report was due, but I will follow up. [note: he had a minor injury after our first meeting that slowed his progress with the 'homework']
I learned that I still have a lot to learn. I want to continue to learn more alternatives and adjustments/adaptations to make poses more accessible. I may never be able to convince someone that they need to use a different pose than what they have in mind, so I would like to have enough knowledge of alternatives that I can always find something else to offer.

I think I would start out in the same way - ascertaining the client's goals and assessing their current state.
I like the idea of trying to offer just the right modification, but with the understanding that the goal of yoga may not be the client's goal right away.
Here's an article about men and yoga where it talks about men often wanting a 'quick fix', but also the benefits they get from a yoga practice once they give it a try.
https://www.courier-journal.com/story/life/wellness/fitness/2015/08/31/men-yoga-find-benefits-challenges/71447610/

I was happy with my ability to see where the areas of inflexibility or weakness were, and to come up with what I think are helpful exercises to help with those.

Ideally, I'd have many weeks to meet with a ct like this so I could follow their progress.

Mark Stephens in Yoga Therapy reports that we can offer support through adaptive practices 1. In a safe setting; 2. With modifications that help reduce further injury [in this case with the knowledge of ct’s spinal fusion]; and 3. Asanas can be done in a way that maximizes efficacy and minimizes harm. I feel that I did plan and act within this, so I think what we were able to do did go well.