I'd suggest he'd probs settle quicker and easier with milk at 10.30pm too. The clue is in this bit:
My 7 month old used to... For the past month he...
So since 6 months? Since weaning?
Early weaning is a really tricky time in terms of calorie intake. I am not kidding when I say it's like going back to newborn days when baby spends almost all of their awake time in the day eating. It's really difficult to fit in all if of the milk feeds baby needs, along with 3 solids mealtimes, around daytime naps.
How much milk is baby having, compared to pre-weaning?
See, most early weaning foods are low calorie - fruit, veg, lean meat. Plus portion sizes are often still small in the early weaning months.
The most calorie dense foodstuff baby can have is milk. So when early weaning (6-9 months or so), it's really important to maintain the amount of milk he was having before weaning started. In fact because baby continues to grow and develop new motor skills, more milk may be required per day post-weaning, compared to ore-weaning.
The idea should be that early weaning foods are on top of milk, not instead of. This is the reason night feeds make a reappearance at this age - to allow baby to catch up on missed calories lost through the daytime because low calorie food is replacing milk feeds.
Once portion sizes grow and the child is having a full compliment of all food groups and snacks, that's when good starts replacing milk.
Until then, if you aren't able to fit in milk feeds around mealtimes, they are likely to be needed at night too. This low-level hunger (by that I mean not enough cumulative calories over the whole day, rather than hunger at a specific time) can give rise to light sleeping. Which makes settling to sleep more difficult even when given milk.