My baby is 3 months old and rolling onto tummy constantly. He still has trouble rolling back onto his back. What can I do at night? He continues to roll onto his tummy most times freeing his arms and head but occasionally getting an arm stuck. I am worried I will find him face down on the mattress. Each time I roll him back to his back however I am unable to stay awake all night.. any advice?

Red Nose recommendations are to “always place baby on back for sleep” not baby must always sleep on their back.

Most babies will be rolling over by 4- 5 months. Some earlier, some later.
This is very normal as babies grow & become stronger.
Many babies then prefer to sleep on their side or tummy.
This is not something that needs to be stopped. It is important to make the “new” environment as safe as possible.
https://rednose.org.au/article/what-do-we-do-now-that-a-baby-has-started-to-roll-over

Are you still wrapping him? Is he in a cot or still in bassinet?
Now that he is rolling, it is important to move him to a cot & to stop swaddling/wrapping.
Babies need the space of a cot & “arms free” to move well

Ensure mattress is firm & flat & nothing soft or loose in his cot.
Continue to always place your baby on back for sleep.

What happens if you roll him back when you see him sleeping on his tummy?

How does he go with tummy time when awake?
Increasing tummy time when awake is important to build upper body strength to roll well (both ways)
Is he rolling from tummy to back during tummy time, holding his head well & reaching for toys?

Parents are not expected to sit up all night observing baby. This is not achievable.
That’s why it is important to ensure his sleep environment is as safe as is possible - firm, flat mattress with no loose bedding or soft items in the cot.