Not the best qualified to answer, but have just found this on anthony nolan site.
What happens in a donation:
There are two ways of collecting the vital cells needed to perform a transplant. Neither involves surgical intervention, although one requires a general anaesthetic.
The first and original method is directly from the bone marrow
Bone marrow is taken from the pelvic bones using a needle and syringe. The procedure lasts on average about half an hour and is performed under general anaesthetic. This method requires the donor to spend two nights in hospital: the majority of donors normally leave hospital the following day.
You are likely to feel tired and a little soreness in the lower back : donors are usually recommended to allow themselves a five-day recuperation period. Bone marrow removed in this way takes about three weeks to regenerate.
The second method is directly from the blood stem.
PBSC (Peripheral blood stem cell collection) Harvest, the other method, is even less intrusive. The donor receives four or five daily injections of G-CSF (Granulocyte colony stimulating factor) . This boosts the production of certain white cells and encourages blood stem cells to move from the bone marrow, where they are made, into the circulating blood stream. The daily injections are usually done in the donor's home by a visiting nurse.
The harvest itself is performed as an out-patient procedure. The donor's blood is removed through a cannula placed in a vein in one arm and passed through a blood separator machine, in a process known as an apheresis machine. This separates the stem cells from the remaining blood, which is returned to the donor through a cannula in the other arm. This process requires one or sometimes two collections on successive days: each takes 4-5 hours. Flu-like symptoms and some general bone / muscle aching can be experienced during the period G-CSF is being administered, but these resolve quickly after the collection and donors can generally resume their normal routine inside 24 hours. The donor may also experience discomfort where the needle is inserted and a temporary tingling in the body from the anticoagulant used to keep the cells from clotting.
All blood stem cell donations from Anthony Nolan volunteers take place at one of the specialised centres in London. The blood stem cells collected are carried by a personal courier to the patient?s transplant centre.
And can I just say, what a fantastic thing for your husband to be doing.