In sleep studies (the kind with video cameras instead of parents reporting) it has been shown that people wake up periodically through the night, and if they need something altered in their environment (covers fallen off, too warm, thirsty, etc) they wake enough to deal with it, and if they have no pressing needs they fall back asleep without noticing it's happened.
The same is true of babies and young children, who do not typically sleep throughout a night until they are beyond 4 years of age. No matter what their parents may think is happening.
If your 10mo is waking in the night, and more importantly, waking you in the night, it is very likely that he is simply hungry, lonely, in pain, uncomfortably warm or cold or something else that he needs that he cannot attend to alone. If he was 'fine' he wouldn't wake any further than anyone else does in the night.
The real issue is making sure everyone is getting enough sleep overall -- throughout the whole 24 hour period. If your son is still napping, he is probably getting sufficient sleep even if you're not, particularly if you are no longer napping.
Some easy ways to make sure everyone gets the maximum amount of sleep available is to make everything that might be needed in the night ready at hand, so much travelling through the house is unnecessary. Keep spare diapers beside the bed, sleep in the same room together, keep a snack or a drink handy (in a way that is also safe -- dry foods and water last best on bedside tables), respond quickly to needs rather than lying there (awake) hoping the needs will go away without attention or that the child will learn sooner rather than later that when it's dark out no one cares what they need, because that just makes everyone miserable.
Penelope Leach describes the pattern of that last issue very well in Your Baby & Child, Birth to Age 5: if you get up and go at the first signs, figure out what is needed quickly and deal with it, you can be back in bed and asleep in under 10 minutes.
If, on the other hand, you 'hold out' hoping the need will go away, you will be lying there until you or the child 'gives up', probably at least 20 minutes just for that. If you give up first, then you have to calm the child down, which will probably take another 5-15 minutes, attend the need, which still only takes 10 minutes, and then get back to bed and to sleep when you are really awake and alert and probably not a little bit frustrated and wound up, meaning it's going to take another 15-20 minutes to get back to sleep. If the child gives up, after 15-45 minutes of screaming in pain, hunger, terror or discomfort, you have still got to get back to sleep with a body that has responded to all kinds of chemical signals and is now completely alert and not just a little wound up, call it another 15-20 minutes to get back to sleep.
The simple, fast and restful way takes 10 minutes. Even three times a night, that's not a big deal.
The 'right' way (according to people who are somehow convinced that children wake in the night in order to endanger their lives by infuriating the people who have the ability to starve them or throw them out the window if they get mad enough) means no one in the house is sleeping for a minimum of 30 minutes each 'waking' and probably closer to an hour or an hour and a half. Big problem.
Lots of three year olds sleepwalk, experience nightmares and night terrors, and all of those are a symptom of a developing brain, stress during the day and insufficient rest throughout the day (flickering screens do not qualify as 'restful'). You can help her understand her power to control her dreams by talking about choices during nightmares, but generally the only thing that really works for nightmares, night terrors and sleep walking is to slow down life to a pace a real 3yo brain can cope with and wait for them to outgrow the stage.
