Is it permissible for a sick person to pray while having a glucose IV drip that provides him with fluids, and does this invalidate the fast?

That which is connected to a patient's artery to supply them with energy does not, in itself, invalidate the prayer. Their prayer is valid as long as it does not prevent them from standing and performing the other pillars, because what is forbidden in prayer is eating and drinking, and this is not considered eating. If the patient is able to remove it to perform the prayer, there is no doubt that this is better. As for fasting, it invalidates it because it is like nourishment that invalidates the fast.