Yes, and you and your DP should have prevented it by realizing that while an older person who is in ill-health might be OK watching an infant, once that child reaches a toddler, they need more supervision than she could provide. You've learned that lesson. I wonder if DP is feeling just a titch guilty because he thought "gosh, she's really not up to this" but didn't say anything? She didn't harm your child, she allowed your child to be harmed, and there is a difference. Your DP needs to see that.
Have any of you had a grandparent harm your child, how did you handle it? <snip>
DP says no way, never. He is toxic talking about her. He is treating this as if she took a bat and struck the baby, or threw him off the deck with her own hands. Mind you, they have never liked each other or gotten along. But now, it’s horrible. He wished her dead.
This worries me greatly. This is not healthy behavior or a healthy reaction. What would your dp do if you said "My mother is an important part of my life. I'm inviting her to Thanksgiving." Why does he get to dictate who comes or doesn't come? If he holds grudges, 'wants her dead' and won't allow her to see her grandson even supervised, you've got bigger problems than daycare. In my eyes, it's borderline abusive. Is this a safe situation for you to be in?
Let me get this straight: Your son was going to your mom's because your DP wasn't able to be a SAHD? Is he working? I'm going to suggest daycare and/or your dp learning to be a SAHD a few days a week. I'm not entirely sure why leaving your son with an older person in ill-health who smokes is somehow better than daycare a few days a week. Toddlers take a huge amount of energy and attention, as you well know. Personally, I prefer daycare because the workers get a break, there's more than one person, and it's their profession. Are your parents trained in infant CPR? Do they understand appropriate child development? His mom, who is younger and more fit, might be able to do it a few days a week, but not 5. That's too much to ask. Yes, daycare costs a lot of money. I'd also remind you that you get what you pay for.