Point taken, I think he just has to be very careful though about not mixing
faith in God the Father, God the Son and God the Holy Spirit, with other Eastern
mysticism. When he refers to the third eye and the pineal gland, our antenna etc, its very
much based on Hinduism and Buddha. Look up third eye on the internet and you will
see what I mean. Maybe your friend needs to focus on the health aspect alone until
he is sure about certain elements of his Christian faith.
I would use terms such as God the Holy Spirit communicating with our born again spirit etc,
We are body, soul and spirit.
There is an extract from the second link you posted below and you will hopefully see
what I mean. I'm also not certain what he means about communicating with other
entities other then the Almighty. Or the idea about other realms. Again this sounds like
Hinduism which sees God in everything and why cows are considered sacred!
I know that mindfulness is very much becoming fashionable but this is based on Hinduism as well.
It sounds like your friend might have been exploring the ideas behind mindfulness and getting
a bit mixed up.
Incidentally there is nothing wrong with being a born again Christian and being
a fitness and health instructor. It's just that if a person is going to mix the two and promote
the two, then they have to be clear about what they believe even if it means losing
part of their audience.

Otherwise it will be a big turn off to Christians who think
he isn't really a Christian, and it will also be a big turn off to non Christians who are not
interested in "religious" ideas at all. So he will end up with no audience at all.
I dont really want to be posting on a strange website about the authors ideas etc.
I have other ways and means of keeping fit. But maybe you could ask him about all
of the above, or show him this post.
Most people don’t realize that our bodies are electric and are capable of broadcasting and
receiving signals. It is my theory that the pineal gland, the third eye, is the antenna of the body.
It sits in the center of our brains. I will do a post specifically on the pineal gland because it is
so interesting, but for now just know that it holds certain properties and has history that backs
the idea that it is the antenna. Our emotions and thoughts are like the tuner on a radio.
This helps us dial in the frequency of what is being transmitted. Love, gratitude, peace and
faith in Yeshua (Jesus), tune us into the Creator. This is like the password that connects you
to the internet. This is basically prayer explained. God created us with communication devices
into the other realm. Does this also mean that we can communicate with entities other
than the Almighty? Absolutely!
People have been communicating with the other side of the veil for millennia. Again, too
large a topic to cover now. There will be a post dedicated to it entirely. In another post
on prayer I will also explain the physiological effects of the body during fasting and how
it effects the power of prayer.