Medical oxygen use?

We have friends who may be using industrial oxygen (like for a cutting torch) to treat their father. He is a heart patient who was just recently released from the hospital after suffering shortness of breath and exhaustion. He was treated approx. 8 weeks ago with angioplasty.  His recent hospital stay included rest and monitoring.  When they got him home he said he wanted some oxygen so they hooked him up to their industrial tank.  This morning he claims he can't remember anything since his stay in the hospital 8 weeks ago, even though he has been out and about since then to church, shopping etc.  Could this be a "bad" kind of oxygen that could cause this memory loss?  BTW--he's 88 years old.  Thanks for any info you could provide.

[National Jewish]

The oxygen, whether industrial or medical, would not result in memory loss.  It is possible for too much oxygen to result in carbon dioxide retention and this could cause memory loss.  Oxygen should only be given as directed by a doctor.
Please encourage your friends to notify their father

[PAUL.B.OK]

This type of Oxygen is not pure 100 %.
It contains enough oxygen for a cutting torch to work but it also contains other (unknown) gases which may be harmful.
Pure oxygen is expensive to produce and that is why industrial oxy is cheap to produce, because it is not pure.