LO (7 months) wakes up screaming

Hello all, our baby boy is 7 months today, EBF and not sleep trained. He has never been a good sleeper, but since he is still sleeping next to our bed I can manage with that. However, since he is 3 months, he has these crying fits in his sleep. He starts to cry/scream and nothing helps to console him. He doesn’t seem to be fully awake (eyes closed, trashing around) and nothing helps to wake him up either (lights on, talking/singing to him, etc). It’s almost as if he has a nightmare but isn’t able to wake up from it. This happens usually before we sleep ourselves, so he is alone is his room them.
does anyone recognise this and know any reason for why this might happen? It really sets me off and ruins the rest of both of our sleep.
thank you!