We are in very similar situations. Java isn't old but he isn't a chick, he'll be 10 in May, but he's very inactive, terrified of everything, and has no idea what to do with a foraging toy. So, what I've done to sort of introduce the idea of eating out of something that isn't a bowl is take fresh vegetables (sliced carrot, head of broccoli, or a stalk of kale) and clip it to his nearest perch without making it to challenging to get to. Most of the time, he'll just take chunks out of the vegetables and throw it on the floor but he'll eat the broccoli florets from the head. This is as close to foraging as I've gotten for now.
He has about five different foraging toys, but because he's inexperienced and inactive, he doesn't use them. I've also taken a coffee filter and put a treat inside it, wrapped it up, and then clipped it to the side of his food bowl so he has to make an effort to get to it. It hasn't worked out much because, since he has one leg, he can't hold anything with his foot to eat like a two-legged parrot could, so he ends up dropping a lot of his treats and toys. So, a lot of the times (most of the times) I have to hold something for him to open: a treat, in-shell nuts, or even just pieces of food that are too big for him to hold. This is the hand that he was dealt, and he'll always need assistance for the simplest things: scratching his head, cleaning his tail feathers, retrieving a lot of dropped toys that he can't get himself, helping him perch, etc. Essentially, he's a sitting duck (he also doesn't know how to fly), so he relies on me quite a bit but I'm always looking for creative ways to accommodate his needs so he can gain confidence and independence.
I recently introduced him to in-shell almonds, which he figured out pretty quickly with the ones that were already split, but the entirely closed ones, he couldn't open. So, he threw them down, turning them around in his mouth, but he couldn't grip it, so I let him use my hand as a table so he wouldn't keep dropping it. Well, he expected me to crack it for him because he kept picking it up and putting it in my hand like," okay, fix it." And when I didn't, he had a mild meltdown: throwing his food, biting me, throwing the almond on the floor. My mom and grandmother said I was being mean and teasing him, that I should crack it for him, but I told them that he has to learn. He has to work for his food. It's been two days and that almond still isn't cracked, but I'll keep offering it until he does it on his own.
So, if you can hide treats in easy-to-open things: like a paper cup, coffee filter, or just under a small blanket, and if it's within reach, then maybe your bird can start learning how to work for his food.