We have 5 people 2 are brother and sister one is 5 1/2 and the is almost 4 we live in a 3 bedroom home. How long are they able to share a room

I know of no state that has laws about an age limit.
It is the various state social services for housing and or benefits that have age limits, and each is different.

As noted, if this is regulated at all, it is done on a very local level, usually no higher than county. And then its usually a requirement of social services or housing departments.

From a practical standpoint, once the older child reaches puberty, then should have their own room.

Thank you

Is there any custody issue, is there a step parent causing issues, is CPS involved.

But no there is no laws,

Nothing like that fr chuck. They have been sharing their room with mom.we were just trying to get mom in a mom by herself