S.H.
This is normal.
It is developmental based. ANYTIME a baby is undergoing "new" motor-skills and development... they do this. And yes it wakes them. Because they don't have TOTAL control over their motor-skills NOR coordination to then put themselves back into a proper sleep position that they were originally in.
So yes, you will need to help him. He will wake and cry. This can also be repetitious... but that is "how" a baby "practices" their new skills and coordination. It is natural and normal.
It is also a new movement for baby... so they get tweaked too. They have not "mastered" their coordination yet.
He will NOT get back to sleep on his own... until he is able to master the new skill, rolling over one way, then rolling over the other way... and then be "able" to get back into a position he is comfortable with.
He cannot yet do it on his own.
Keep expectations age appropriate, in light of his new development.
Both my kids did that as babies too.
Keep in mind, this is just the beginning. Other developmental phases/motor skills will tweak their sleep too: when he starts rolling over both directions, when he starts to sit-up IN the crib. when he starts to pull-up, when he starts to Stand-up in the crib... and when he starts walking. ALL of these, will be an instinctual impulse in the baby... because they are developing and hitting new milestones. And this is how they 'practice' it.
Then there is teething. This wakes them too. And separation-anxiety.
Whenever a baby is undergoing growth/developmental changes... to me, it is NOT the time to have them cry-it-out. It is not their fault... they are just having a hard time getting their limbs and coordination coordinated.
Another way to look at it is this: be happy he is developing well and normal. Because if he was NOT doing this... then you would worry about his delayed development. So, your son is developing WELL and normally.
This is just a rite of passage for the parent. It is also the baby going through growing pains... which encompasses physical and cognitive developmental phases.
He will sleep on his own... as he gets used to his new motor skills... and then is able to control things at will.
You should also be doing tummy time with him...so he gets stronger trunk muscles too. Which helps. Each baby will attain mastery over their motor movements, differently.
6 months old is also a major growth-spurt time and a time of hitting many milestones. So sympathize with that... and show you are proud of him. They also get hungrier too. So feed on demand.
Every 3 months, is a growth-spurt time... and developmental changes.
All the best,
Susan