Please read & settle an argument!

I am livid so I want to know your opinions and see whether I am over reacting. My little one was struggling to breath on Friday night and we ended up in A&E. We were told the next 48-72 hours would be important as he would likely deteriorate. He has RSV. We have a toddler too so whilst we were in hospital my FIL came over to look after other child and said my MIL (who is currently away on holiday) would be angry he had come over to watch our toddler so we could go to hospital as he had left her dogs at home alone. Now I’ve always found her extremely self centred so this didn’t surprise me in the slightest. For many reasons and not just to do with me and my direct family. The way she treats her husband is atrocious in my opinion. But my husband has always stuck up for her and made excuses, I guess she’s his mum right 🤷🏻‍♀️ Anyway as I said she’s on holiday right now. My husband text her to let her know we’d been in hospital, all have RSV etc yet she hasn’t been texting to check in on how my baby / the rest of us are (we are all ill). The last two mornings I’ve woken up to pictures being sent by her son who she is with and texts saying what an amazing time they are having without a single care in the world about how my poor baby is. My husband is of the opinion she’s on holiday and should just be enjoying it. She’s doing nothing wrong not checking in, says she might not have internet blah blah. Which they clearly do as like I say her son is texting and in my opinion even if she doesn’t have internet she could ask him to ask. Also what hotels don’t have free Wi-Fi these days!! I am disgusted. I do not want to see this woman again, otherwise I might really tell her what I REALLY think of her. She’s certainly not type the person I want anywhere near my children. Is my husband right? Am I over reacting? My family and friends are all texting daily for updates and are extremely worried about my little one as he is only 16 weeks old. Obviously I am very sleep deprived and emotional right now, seeing you’re 16 week old struggling to breathe is heart breaking but would love to know what you all think / make of the situation 💔