Can separate people claim children

I’m sorry, I didn’t know how to word the title.

Here’s our situation; three adults, one house, my four kids. Myself, my husband, and my adult 24y/o brother. My husband and brother are both roofers on the same crew. They combine their income to pay bills, buy necessities, go grocery shopping, etc.

 Tax time is around the corner and my brother asked if he could claim two of my children because he supports them financially just as much as we do, he lives with them year round, and changes diapers, cooks for them, helps them with homework, babysits when I run errands, etc.  I am totally fine with that, if it’s legal. So, is it legal for my husband(the children’s father) to claim two of my children and my brother(their biological uncle) to claim the other two because they supported them equally?