This is rough. Your wife is lucky she has you to help her and to take care of the kids while she cannot. Too bad the family isn't on the same page with you. Can you take family medical leave from your job? If you are unaware of this, here is a link to some more information about it: http://employment.findlaw.com/family-medical-leave/family-and-medical-leave-act.html?DCMP=GOO-EMP_FMLA-States&HBX_PK=family+medical+leave+act+new+york.
I cannot imagine the stress this must be putting on both you and your wife. If the family is going to be more of a pain than a help, it might be better to hire some help. Sometimes medical insurance will help cover the cost.
Both my wife and I have sciatica caused by spinal arthritis or spinal degeneration. Margie is seeing a spine doctor later this week to discuss her options. I have been dealing with my sciatica for a couple of years. Once physical therapy is done for my knee, I will also look into what I can do to relieve the sciatica. Mine is cause by arthritis while my wife has at least 4 discs while have no cushion left at all. She is not healthy enough for surgery so she will be limited to steroid injections. This might be the way I'd prefer to go too....at least at first. Of course, both my wife and I have this condition because we are old and because some of our parts are wearing out. 
Hang in there Steve. You're a strong man....and I'm not talking about your muscles. Your wife is very blessed to have you to help her get through this. If you can, ignore the meddling family folks and don't let them get to you. Arguing just adds to both you and your wife's stress levels and that won't help her heal. Stress is not good.
AT THE END OF THE DAY YOUR KIND WORDS DO MATTER AND MAKE SENSE,I WILL TRY MY HARDEST TO KEEP MY TEMPER IN CHECK AND DO WHAT I CAN THIS WAS MY DAY YESTERDAY AND COULD CHANGE FOR A BIT 'THANKFULLY I HAVE DECENT HOME GYM TO SNEAK TO OK READY..
LEGS
SQUAT 135/225/275/315/365/405 12/12/10/10/8/6
LEG PRESS 5/6/7 PLATES12/10/8/ PULL OF BACK TO 5 PLATES 10 MORE
WALKING LUNGES 50 LBS WALK X2
LEG EXTENSIONS 220/230/235
HAMS
SLDL DBELLS 60/70/85
LYING LEG CURLS 140/155/155
CALVES HACK SQUAT CALF RAISE X4
SEATED CALF RAISE X3
THEN
FOOD SHOPPED
COOKED DINNER FOR 5 ,RAVIOLI'2 KINDS'MADE ZUCCHINNI/RED PEPPERS IN OLIVE OIL/GARLIC/PEPPER USED THAT AS TOPPING ON BREAD I TOASTED IN OVEN THEN TOPPED WITH TOPPING AND MOZZARELLA BACK IN OVER ,SALAD,WINE,
3 LOADS LAUNDRY AND FOLDED LOL..
TOOK ALL ORNAMENTS WITH HELP OF KIDS OFF TREE,THEY SPLIT,ALL OTHER CHRISTMAS STUFF PACKED ,BROUGHT TREE OUTSIDE ,AND THEN VACUMMED THOUSANDS

NEEDLES.
I WAS DONE AT 1140 PM TO BED,,,