This sounds rather like a speed-run to end a friendship, if one is not careful.
I get this kind of things can be entertaining among friends during a travel to Las Vegas or drinking some beers and they decide to log onto an online casino to see what happens.
The problem is that the person who gambles, usually is aware that there is a fairly high possibility of losing it all and if the friend is rather new to gambling, then he could have some fake expectations of getting a lot of money out of nowhere just because his "experienced" friend is gambling his money.
So, no I would not do that. It is better to grieve one's own money if there are losses, rather than spoiling a friendship.
I absolutely agree with you. In general I think that in order not to lose friends you need to learn to separate friendship and financial matters. As life shows very often business with friends in the end leads to distrust, disputes and disintegration of friendship. Therefore, friendship is friendship, but in the casino, everyone must play with their own money.
I think I could make an exception if my friend understood it is money that we would likely lose forever during that night.
I would tell him something like "give me what you are willing to lose and if we indeed losing it, we will let it go and not try to get it back by gambling". It is a bad idea to say stuff like "we gonna get rich tonight" or something similar.
However, considering I would be likely a bit intoxicated, it would not be surprising f I joked a bit about it.
... Better safe than sorry, and keep friends and gambling away from each other, I guess. As we agreed.