First I want to say that my son initiated every phase of toilet training himself.
My son started with a small potty that sat on the floor, then he moved to the toilet with an insert so he didn't have to hold himself up, then at some point he ditched the insert and potty himself. We would also let him run around the house without any bottoms on. We would put the incontinence pad on the floor for him to sit on and yes, he had a few accidents but he was aware of them moreso than if he was wearing pants. He was in underpants and trained during daytime and diaper at night for almost a year before HE started night time training. His diapers were still soaking wet every night, but one night he refused to wear a diaper. So a couple times after he went to bed we would literally scoop him up, sound asleep, put him on the toilet and he would usually pee. If we tried to wake him up to go to the bathroom he would throw a fit, so sound asleep worked. After a few weeks, he would wake up crying, we would go in and scoop him up and carry him to the bathroom where he would pee. this progressed to him waking up crying, opening his bedroom door and we would walk him into the bathroom, then eventually he would wake up and run in on his own. We did buy a washable incontinence pad at a medical supply store to put on his bed. And the scooping the sleeping child up advice came from some nighttime potty training book I got from the library--don't remember the name.
We also did a whole sticker/reward program. We got a calendar and phase one was every time he went on the potty and was productive he got a sticker on the calendar. This progressed to getting one sticker on days he didn't have an accident for a full day, and after 40 dry days he got a big toy he chose at the outset. Then when he started nighttime training, he got a sticker every dry night and got a toy after 40 dry nights in a row, which he did almost immediately because he really wanted the toy! He was 3 years 2 months when dry during the day, and almost 4 when dry during the night.
Your son will most likely train easily if you let him initiate it, but you can still have him pick out a potty "for when you are ready so we have it", get a potty book and read it to him every day, point out all the cool big-boy underpants to choose from at the store. When he's ready to start nighttime training, if you are still in the same living situation maybe you could put a small potty in his room for him to use. Be patient and it will happen!