Can u sue the tribal government for wrongful termination?

My husband worked for the tribal government.he worked for them for over two years.he was u.a'd on hearsay of one person who didn't even work in the same dept.and didn't even know my husband.but claimed he was "tweekin"while he was chowin down at a dinner they had(.no he was not)he did test for weed.which he had done 3 weeks pryor.and was a one time thing and he was off the clock!!he worked for a different dept at the same place and then transferred to a better paying job.one day before his 6mo raise they popped a "u.a on hearsay.they have programs that help u.for rehab ect and pay while u go.and after rehab u go back to work. they told us he wasn't eligable cuz he hadn't been there 6 month??? But was in the same tribal job just a different dept .but was a "non-employee ??? the very next day they did the same thing to my brother and he was fired also.with no benifits or offer of the programs he wasn't eligble cuz they said he wasn't an employee?? But another "non-employee to rehab for alchol and didn't even get a u.a and got to keep his job unemployment was denied but becuse the found discrempcies in my bros case he got his unemployment.this is just the tip of it all.any lawyers out there thAt aint scared of the tribal gov??I sure need one.this nation is so crooked u wouldn't believe it.it iz a multi-billion dollar industry NEED HELP!!cus they tell u they cannot be sued cus they r tribal gov??