I'm not into controlled crying or letting a baby cry to sleep on their own, but do think it's ok to allow a small amount of crying while you are there to comfort. Here's my tips and what worked for me.
Is there room in your sons room for a bed? My nursery has the cot but also spare bed in it, and I am able to lie in the spare bed and comfort my child through the bars if needed. So with my daughter, if she woke through the night and I knew she didn't need a feed, I would just lie in the bed beside her and shoosh, pat until she went back to sleep. Yes she still cried a little, but she knew I was there to comfort her and wasn't being ignored, and even though I was "awake" being able to lie down while I comforted her and patted her back to sleep meant I didn't get exhausted, and if we both fell asleep so be it, if she fell asleep before me I'd go back to my own bed. It didn't take long before she just stopped waking up at all except for a feed.
Also ditch the dummy completely day and night, it will suck even more for a few days, but be worth it once it's gone. Dummies are great for some babies and even toddlers, but not those who are waking 8 times a night looking for it. It would be better off gone. Good luck