Ok, quick a brain storm..... I don't know your boy, so it's hard. When you play these, you'll feel how it works, and get ideas that suit you better. See what he likes and responds to.
Bed time wind downs
Give him a foot massage, or ask him to give you one. Feet are a long way away from the heart or head so aren't emotionally threatening... but do give an opportunity to talk about what feels nice, soothing, relaxing, smells good, tickles, etc. Also, like talking on a car journey or while doing the washing up. You are both stuck there in companionable silence, so things tend to get said. You can do head or hand massage too.
Make a sock maze together- lay out a line of socks on the bedroom floor and make it wiggle or spiral about. Walk inside the shape or on top of the sock line (depending on the shape).
Ask him to help you put cream or talc on your feet- they are sooo far away and he is young and bendy! Talk about the smell and feel of the lotion.
Get some essential oils- safe, soothing scents, lavender, geranium, rose etc.. do a scent test. Every evening choose one to put on a handkerchief or tissue one his radiator.
Self care. Show him how to smooth out his pillow, pick a good book, choose comfy pyjamas, make a warm milk (add honey, spices, see what he likes- the choosing is part of the activity). Brush his hair, if he has enough! Choose an audio book. Try and find some ways of babying him, without it feeling silly for him. Take opportunities to coddle him where you can. Touch is so important.
Silly games
Make a [child's name] pizza. You announce you're turning him into a pizza, squash out the dough (firm pressing movements), smooth on some pizza sauce (stroke firmly and smoothly), plop on some toppings (gentle poke, poke, poke) sprinkle some cheese (fingers sprinkling onto him).
Ask him to hide a cotton ball or similar on himself. Tucked into a sock or a pocket, not in the areas covered by a swimsuit. Then pat pat pat all over him trying to find it.
Try blowing a cotton wool ball with a straw. Move it around the table. Make a maze for it and try and blow it through. If you both have straws it's teamwork to try and keep it on track.
Eat a strawberry lace- at the same time! Start at opposite ends, eat till the middle! Maybe make a silly face as you get to the middle so he giggles and let's go.
Put hula hoop crisps on your fingers, and feed some to him.
Eat a chocolate mousse each- but you have to spoon it into the other person's mouth not your own!
Laughter is a great stress buster, as is physical touch.