i will approach this from two different angles, one for each question.
question #1: (without refering to a holy book) Is there proof of "god?"
answer #1: to me, it is quite easy to prove that there is something bigger than what we know, whether it is "the" God of holy texts or not. in fact, science has already established it, though few scientists care to examine the issue from this angle.
the Law of Entropy states, basically, that order moves toward disorder, and only outside energy can shape disorder into order. however, the energy required to create order displaces even more order, so it actually creates more disorder in its quest. i hope that didn't lose anyone.
think of it this way. to make a bar of gold requires a lot of effort. the energy to dig it up, the displacing of soil, energy to transport it to a smelter, and so on. in the end, you have a bar of pure gold (something that has order), but you have created much more disorder (the burning of energy in human activity, fuel, etc., the destruction/displacement of sediment, even the wearing out of rubber tires used in transportation, and so on) so that the small amount of order could be created.
in other words, any action in the universe creates more chaos, and ordered systems can't emerge wihtout outside force. this has been proven so many times that it is no longer a theory, and is now a Law of physics.
however, we are supposed to believe that all the beautiful systems in the universe (mathematics, physics, life, etc.) emerged due to random chance. that is contradictory to the Law of Entropy.
for example, no matter how many times you mix hot water and cold water eventually the temperature throughout the bucket will become even. no matter how many times you do this, the hot water will never somehow separate into a certain portion of the bucket and maintain its system. rather the bucket's contents mix until they become completely without order, and their randomness has become complete throughout the container. this will always happen unless some outside force acts upon it.
logically, if such a simple thing can't take place without some outside force making it happen, then it is impossible for all the phenomenally complex systems that are evident in the universe to emerge from the chaos of a big explosion without some outside force acting on it.
that necessary "outside force" could certainly be titled god. whether it is the god of the Bible or not is another question.
question #2: (again without a holy text) Is there life after death?
answer #2: i've not yet found anything that would scientifically "prove" this notion, but i've heard enough anecdotal evidence to lend credence to it. in addition to the points White Shogun made about every people in history having some sort of belief in it, there are a lot of "life after death" testimonials.
much like anything else, i am skeptical of someone who has something to gain from such a statement (they have a book for sale about their experience, for example). therefore, i am more likely to believe an instance where the subject has nothing to gain, and no reason/not enough knowledge to lie.
one such instance in my past meets this requirement. a friend of mine had a very young niece, one just old enough to talk and make sense. she was three, i think. anyway, this little girl LOVED pillows. they were favorite thing in the world. she also got really sick (cancer i believe) and was in intensive care. things began to look very bleak, and one afternoon when her parents and my friend were in the room with the little girl, the little girl spoke to them.
she said something to the effect, "he says it's time to go."
"who?' asked the mom.
"the man by the door," she replied. of course, there was no one there. at least, no one the adults could see.
seeing their confusion, the little girl said, "don't be sad, mom. he's already shown me where i'm going. and i have a room with nothing but pillows. i just wanted to tell you not to worry before i left. he says it's time, now. goodbye."
that's a true story, and the little girl was in a family that didn't go to church. i am of the opinion that my friend who told me had nothing whatsoever to gain by lying.
something happened. but only questions of faith has offered me any answers as to what.