Hello,
The same thing happened to me. I was asked to come back one month later and after two further collections I had plenty. I should mention that I am in Luxembourg so perhaps the procedure is slightly different. I would suggest asking your hospital/consultant.
I will start my SCT next week and as I have a high risk version of myeloma will have a second SCT shortly after.
I’m sure it will work out for your husband. Chin up and all that.