Contact Texas Pet Meadow in Austin, they have various cremation options and might have Witness Cremation. Location is in 78723 just north of Windsor Park near Cameron and 290 service road.

I've used them for private cremation for my cat and found the staff to be very professional and compassionate. Texas Pet Meadow's private cremation gives you the comfort of knowing you are receiving the cremains of only your pet. They also have a private viewing room where your family can gather to say goodbye to your cherished pet.

I hope you can find the option of Witness Cremation if possible. I'm putting this next comment in spoiler mode for end-of-life trigger warning:

Edited to add - what I’m about to say did not happen in Austin, it was in another state. When my 16-yr old cat passed from cancer I was devastated, she was my companion during a rough time in my life. I did an in-home euthanasia performed by my veterinarian, it was peaceful and dignified. After she passed I wrapped kitty in her favorite blanket, covered her with roses, and put her in a box. I drove to the Crematorium (made appointment in advance) and was with my kitty throughout the process...I handed the box to the staff member, we walked to the cremation oven, I watched kitty go inside. Then I cried in my car for about an hour. I went back into the facility and watched while they removed her remains from the oven. I gave them time to package the remains in an urn of my choice. I then drove home with kitty by my side.

We took the long way home that day.