Cheeka: Don't get too alarmed. It's common for Gynae to ask dh to do sperm freezing if the numbers is low. It's also common to do a few freezing until the numbers are enough in their view. Usually the Gynae will refer dh to do a ultrasound and then to see an andrologist. Like the sisters here mention, variococele is a cause and surgery might not help. In fact, if surgery is to proceed, the dh will be asked to produce enough sperms since surgery might cause no sperms too. Did your Gynae prescribe anything for your dh?
From what I know, if after taking the supplements for 3 months and results do not improve then nothing much can be done. However, IMHO if it don't help ok, as long as it don't get worse. Take more antioxidants, no cycling, boxers, no alcohol, oysters. All the basis.
Another thing, it's not necessary true that to abstain longer is good, my dh told me. 2 weeks is definitely out as the sperms get too old. Trial and error what works for your dh instead on storage.
It's also possible for doc to retrieve sperms from the testes but usually not practice here (it seems) as its invasive. Normally if there is still sperms that fulfil the criteria for ICSI, it's good enough since u only need that 1 sperm per egg.