There are demons in my boyfriend's house! What do we do? Please help!?

Well, Lets think rationally and logically here, not religiously.

Has your boyfriend had any mental disorders in the past, including depression, bipolar, or any other mental illness? Or has he taken any drinks or drugs recently?
The voices could be hallucinations or voices in his head. When one is drunk, or is High/Low from drug use or abuse, it is common that people hear voices. You say he is religious, or you imply so with the cross. Hallucinations are a bit like dreams, they are subconscious thoughts, except you release these thoughts. Your boyfriend only thinks or believes God is real. He may not be real - but he believes He is, so he could have an erratic thought about the matter.

Doors opening and closing would be a simple explanation. I live in quite an old house and that happens ALL the time, especially when it's windy. Ensure your doors are shut properly, and if not, wait till the weather or draft dies down

The cross flew across the room? Well, I presume that's not the only thing to fall. You only mention the cross because it has significant importance to you regarding your religion. If the walls are old, it's not uncommon for things to fall of walls or shelves. Again, if it is windy or stormy, then this is common, even if the walls are new.

The dogs barking. I imagine it's only a storm or gale force winds again. There is a lot of noise and discomfort for them.

The shadows? See the hallucination bit.

Deaths has nothing to do with this.

EDIT:
Or your boyfriend might just be having radical thoughts, or lying to you

Lol Demons saying "there is no God" yet they present themselves to humans to show you they are real, thus leading you to believe God exists. I really hope this is not a serious question.

dial 911

Demons? Uh oh. I can only suggest one thing: CALL CHARLIE SHEEN. He will bust a 7 gram rock on their domes and destroy them.

P.S. Your boyfriend is looking for attention from you and there are no demons in his house.

You should see the house for yourself and get to know.Call a priest to bless the house.Burn sage chanting holy words.If this doesn't work,best to contact a psychic.:-)

Tell him to get the F**** out and get profesanals i ther him fist then the dogs demons feed on fear or tell him to grt in a small room with nothg on shelf stuf they could hert him with lock the door and weight it out tell him to stay calm and it might be hallucinations rember you minded is the only thret to you

If you can get him to record it for evidence later

Immediatly: get the F out of there.

ASAP: Burn (Smudge with) white sage.

Then mak the sence of your religion oe what you believ known. So since there was a cross on his wall maybe set a couple up around the house with pictures of jesus and bibles. You may want to get someone that can feel the presence of spirits or the presence of negativity and positivity in the house to come check it out and feel where the negativity is coming from. So many people are actually able to get feelings off of things its crazy about 1/3 of the people around just some can feel it more than others.

****IMPORTANT****
BE KIND don't be all "hey you mother efers the efin fight biotch" no they may not be demons they may be scared spirits.

If you cannot find a medium do something very controversy and possibly dangerous in this situation. Get or make a Ouija board. Google some rules and bam play but be smart.

Ask around at local wiccan stores for help.

You'll be fine and remind everyone participating in helping to remember be kind and if it is a demon. Then it feeds on fear.

Hmm, go into the house, with a priest and bible, and have an exorcism performed or one could move

Either your boyfriend is lying to scare you or mess with you, or maybe he's had a history of mental disorders or still has a mental disorder. Schizophrenia is a mental disorder that involves heavy hallucinations. Or maybe he's taking some sort of hallucinogen you dont know about and it's making him see things. of he's mentally stable and these things are actually happening, WELL THE OBVIOUS ANSWER TO YOUR PROBLEM WOULD BE TO TELL HIM TO GET HIS DOGS AND LEAVE THE HOUSE ASAP !! Tell him to go somewhere populated where he'll feel comfortable, preferably where dogs are allowed. tell him to try looking for a motel or inn or hotel or WHATEVER where dogs are permitted and he could stay the night there if he really feels he cannot stay at his uncles house any longer. Also, tell him to tell his brother and uncle everything he's seen

You go there and relieve him from that home, or call to him for come out that home .
or you go to that home with ghost riders or priests or paranormal researchers .
You do something.