Very difficult period ( deaths in family, redundancy) taking toll on married life. Help please?

Our my marriage is going through a difficult time after rollercoaster couple of years my husband and I seem to be constantly arguing as he is unbelievably tense, touchy, hyper-critical and tired and withdrawn. We had our beautiful baby girl who is the light of our lives 2 years ago but immediately after her birth one very close family member ( his aunt who brought him up) died of terminal cancer-my husband had been with her various times during the pregnancy and at just one month old we took our baby to be with her during her final days then organised and paid for funeral and sorted out all legal affairs and paid all debts. My husband's father then became ill with terminal cancer just 6 months later- we were the mainstay throughout chemo, home care etc I did as much as I could but my priority was the baby..A very painful 9 months followed as family refused external care until the very end. Another close family member died 1 month ago and agin we took on the brunt of it all. In the meantime, we have had to financially bail out his sister who is unemployed and a compulsive spender and mega in debt. I was then made redundant and as I have a spinal disability work especially in the recession is hard to find. My husband is very withdrawn or mega on edge and it seems that it is one problem after another-he has just been diagnosed with glaucoma which has frightened him but for the moment the doctors seem to have it under control. We have been going to marriage counselling which does help but we have little time or money which is compounded by the fact that we are trying to buy a house as where we live is on 4 floors and is impossible for my back. I try to tell my husband to look on the bright side that we have a precious wonderful daughter, he has a job and we have a roof over our heads and no terminal illnesses but daily life seems a real grind..Any tips for breaking the argument cycle and getting our marriage back on track...Any constructive advice would be great..Thanks in advance.