TLDR: 3 year old cat is waking me up every night because he's bored I think. All the toys I've tried have failed and kitten seems very anxious.

About 2 weeks ago my 16 year old cat passed. Despite his age it was a bit of a shock because 2 weeks before his passing he was in for a vet appointment and they said he was in perfect health. I'm mentally still not ok about it, but not the real problem atm.

The problem I'm now dealing with is ever since then, my 3 year old cat wakes me up every night. He just wants me to refill his treat toy, but he never did this before, I also refuse to fill said treat toy until 8 am when I normally wake up. I figure this is why is because as soon as it's 8 AM and I fill his treat toy he happily goes at it and then once his toy is empty he relaxes. So I'm hoping he'll give up and accept that I don't give him treats until morning and refuse to.

I feel like he's just bored since the cat he's been around since he was 6 weeks old is gone and it was his friend. We've tried different toys, but he doesn't care about any play that isn't another person/animal or involves treats.

Like he'll play really friendly with our dog, but our dog sleeps during the night. He also played pretty gently with our old cat, and loves playing with like fishing poles. But I don't think we ever taught him to play by himself since he always had someone to play with and now doesn't. He was a covid kitten that "might" have slept almost all the time in my arms as a kitten because held him for like 8 hours a day and he slept there. Working from home with a young kitten meant he was very spoiled.