If my name is on a title to a double wide, along w/ my roommates, do I need to claim if I know that he is claiming it since it's half mine?

Each person is entitled to claim their percentage share.   Sounds like you are entitled to 50% ownership unless you two have another agreement.

In order to deduct mortgage interest and property taxes, there are two requirements.

1) You must actually pay the interest and taxes.

2) You must be legally liable for the debt or hold title to the property.

If you are both legally liable and both make equal payments, you should each deduct 50% of the mortgage interest

and property taxes.

In other words, you should deduct according to your liability and the dollar amount of the deduction you paid

Property taxes and mortgage interest are owed equally by all co-owners. That means that if you are a 50% owner but you pay 100% of the property tax and interest, you would be allowed to claim 100% as an itemized deduction. On the other hand, if you are a 50% co-owner, but you don’t pay the tax or interest, then you can’t deduct anything.