My GCC loves cockatiels

[Tango’s mom]

I recently went on vacation and a friend offered to look after my green cheek conure, Tango. My friend has 2 cockatiels and Tango is totally in love with them. They go back and forth into each other’s cages and Tango even wants to sleep in their cage, instead of his own. I just got back yesterday and will pick him up tomorrow.
I am worried that after 12 days with his friends, he will be lonely when he comes home.
Should I get him a friend? And is it unusual for a conure to get so friendly with cockatiels?
He is 4 yrs old.