How do we overcome his arguments? Simple. Live our lives purposefully and without gods.
That's his point, even if we live without God it would be absurd.
And my point stands. The value of someone's purpose in life is completely subjective. It would be absurd to try and convince someone of this basic concept when that person is a true believer in a cosmic purpose. Living your life with purpose (whatever that purpose may be) and being happy is a great way to prove them wrong even if they never understand that they have been proven wrong. In most cases, their delusions will prevent them from being swayed by any argument made, so why bother? People sitting on the fence and spectating may better see that a person's purpose in life does not need to follow a single, religiously prescribed path when they see examples of it.
I have not found an iota of validity in the arguments of theists. Their idea that our short lives on this rock are meaningless without a "sky friend" is amusing. As a previous poster stated: purpose and meaning in life is entirely subjective.
I would agree with him, and counter with: "So What?"
Why does there HAVE to be a purpose?
He ends with "please consider Islam" or in other words "please consider submission" and "please surrender your critical faculties" and "please do not ask questions". What a high price to pay for a placebo effect of happiness.
His entire so called 'argument' is in fact not an argument at all, as he is merely asserting that god exists, for which, at present, there is no evidence; ergo, his statements are baseless.
I would say our purpose in life is what we make it, as cliched as that sounds, it is so true. How ridiculous is the belief that we need a divine dictator to make us happy on pain of eternal torture? No superstition is necesary for a happy life, in fact, I believe it subtracts from it.
Placebo effect... I like that.
His opening example of being lost begins with the presupposition that we have no original starting point. To wake up after being unconscious and finding oneself in a new environment is bound to generate the question, "Where am I?" but that does not mean that we have to ask that question when we already know where we are. It's a false comparison.
His next argument - life is meaningless without God - is also false because he assumes that an atheist cannot have meaning and purpose. He makes no attempt to support that claim.
As often happens in such arguments, he conflates meaning for an individual with that of humanity, suggesting that atheist thinking says mankind has no meaning, and he tries to emotively suggest that therefore, individuals ultimately have no meaning for their lives. This kind of argument plays heavily on the minds of shallow people for they desperately want there to be meaning for themsleves when, without God, they cannot see any.
The obvious response to this is that there really is meaning for each individual's life, especially if they have friends, family and influence. If they cannot find happiness in that alone, then they are sadly lacking and deserve the God they hanker for.
However, ultimately, there is no meaning in the bigger picture because, if there was it would suggests a purpose designed by an external entity. This is one reason why God was invented, to give meaning for those who felt inadequate when considering the alternative - the reality - that ultimately there is no purpose to humanity, life or indeed, anything.
People don't like the responsibilities of their lives on their shoulders. If where your life goes is based on what you've done, if it's not what you want, then it's disheartening. So people need a god or gods to have that responsibility, as someone to blame or claim that they have a plan for them that they can't know.
Belief in those gods is still an example of inventing your own purpose.
But there are so many more different things that we can work towards that can give meaning to life if you so desire it. Advancement of humankind, art, music, science, hell, if your goal is to be the best damn polka dancer, that should be enough. A lot of the comfort and learning people find from religion can easily be found outside of it if they actually look for it and think.