prepaid 'dumb'phone would be a great idea so you can still be in communication with the world on a phone, sms/phone calls. Internet on your phone not really necessary. He is ok with internet being shut off at home?
Can you ask your parents to sponsor a few maternity clothes *now* rather than fancy shower gifts later?
I buy used. Go on ebay and search for 'maternity lot xs' and you will find people unloading their whole maternity wardrobe for what just 3-4 pieces would cost at Motherhood Maternity at retail. You'll get dozens of items gently used that way, and feel like you have plenty of clothes to alternate between.
What does he say to the fact that internet is getting turned off, your car payment is going to be late, there's no food in the pantry, nor toothpaste? Is he ok with the fact that he can't provide basics? Are your parents able to spot you guys a loan for vitamins/food/basic household supplies for awhile? If he can get a better paying job or perhaps some odd jobs on weekends or evenings like I suggested earlier since he wants to be physical and sweaty many hours per week (lawn mowing, landscaping in general is a decent way to get more income for the family as well as work off some steam when he isn't teaching)....that may help a lot.