Good morning, @anitasharma. It sounds like it’s a ‘go’ for the bone marrow transplant! I’m so happy your son was able to be the donor! What an exceptional gift to give his dad…the gift of life. ☺️
I think you and your family have done an amazing job of preparing for this next transition for your husband. Keeping in mind most of us who have these transplants have no serious long term side effects. But without the transplants, we’d no longer be gracing the planet! I’ve yet to talk to any of my acquaintances who wished they had not gone through with the procedure.

Of course, as with any medical procedure, there are some potential risks, especially with a reaction of the new cells to the body called Graft Vs Host Disease or GVHD. But most incidences are handled quickly with steroids or another medications. There are newer meds on the market that pre-empty gvhd early on. Some gvhd issues may become chronic but we learn to roll with the little inconveniences. Personally, the past 6 years that I’ve been on this planet are bonus years and I’m relishing every minute of being alive. It’s perspective. ☺️

You might find this guide from Mayo Clinic helpful. Each clinic will have their own protocol for procedure. But the basics will be similar. This guide has several parts for Caregiver, The transplant journey, etc. Your husband will be having the Allogenic transplant. So skip over the autologous transplant.
https://connect.mayoclinic.org/blog/caregivers-for-bmt-car-t-and-hematology/tab/transplant-journey/#ch-tab-navigation
Is there anything I can help you with? Any specific questions or concerns?