Is my cat in heat and spraying or is it something else?

[KUKI]

I have an 11 year old male cat and I just got it neuterd 2 days ago.
Before I got him neutered the following was my observation:

-sometimes he urinates just outside the litter box and other areas of the room
-he waits for me to change the litter before he pees or poos in it again the second time
-he squats when he pees in other areas other than the inside of the litter box
-the urine smells very unpleasant and unbearable
-he meows a lot
-likes to hang around the window lately

Do you think the cat was in heat and spraying or is it something else?
If he is, what are the chances of this behaviour stopping?
Is there any medical procedure (surgery) or treatment that can eliminate the unbearable smell?

I hope you guys can help me on this one. Thanks a lot.