My dad worked 6 days a week when we were kids, and my mum was self employed and technically the sole carer, although we spent a lot of time with her father. My dad's parents not so much. I always knew he loved us, he was interested in us, he came to school events and kept up to speed with friends and gave us lifts, taught us to drive.
I remember him seeing a lot of his friends, and had a better social life than my mum, but now she's gone, I am glad that he has old friends and company and people to relive memories with.
I can't say I knew him really well until I was an adult. We have similar interests and I find him interesting, but I think that's because it was always important to him to be there for us. Always interested in us. Yes, he worked 6 days a week, I see now he was providing for us, but Sunday was always our day, us without mum, probably to give her a break! He took us mountain climbing, rode us for hundreds of miles on bikes, fishing, swimming, to see his parents, to see his friends & their kids, we were up early on a Sunday and out, and home on time for lunch, even if lunch was 5.30pm, there was no concept of time on a Sunday, but you knew it was coming to an end when he bought the paper in the way home, he was getting ready to clock off, eat his dinner, read the paper and have a beer, while we had a bath and got ready for school.
My dad probably thought he was better with the boys, but he taught me all the DIY I need to know, how to clean my shoes, and he dried my hair with the hairdryer every Sunday which would have been a mammoth task for him.
Your husband doesn't have to book Disneyland, he just needs to be present, find common ground and take it from there. Earn trust! Mind you're not running him down to the kids, and let them see the nice bits of your relationship if there are some. My child wrecks our cuddles, because I'm not allowed to hug her daddy, or her daddy isn't allowed to hug me, but it's fun. It's good for them to see an adult relationship and how it works.
If they're being rude to him, call them out on it, that's bad manners, regardless if you think he deserves it, they can't be allowed to bully their dad. Ask him why he thinks they speak to him like that, agree it's not acceptable, but he does need to parent, not act like a lodger. Tell him why he deserves it, he can't just make guest appearances in the family and expect to pick up from that nice week you had in Tenerife 4 years ago.
If lockdown hasn't changed him though, I doubt anything will. I work 6 days a week in the same profession as my dad did, but I don't have a wife or mum at home to do all the stuff. My husband and I are equals, I am number 1 parent 60% of the time, him 40%. I run, I'd love to run more, but typically a mother can't, or doesn't want to opt out of family life or time with her children. Unfortunately a father can, or does want to. If he's not coming to the party and you want him to, tell him. I think he should know, but his reaction will tell you all you need to know about the family and the relationship going forward.