calling with any two: debate with a friend and a rough AA hand

[Mariogs379]

FT of 18 person $11 MTT
blinds: 300/600 ante 50
5 people left, friend has T5500 startingi stacks are 1500
friend is BB, shortie is UTG+1 and he pushes his 1100 folded to friend who has to call 500 more into a 1750 pot with 57o...
he says its a waste of chips i say getting 3.5:1 on the call he should with any two...what do y'all think?

AA hand
earlier at the final table with 8 people left i get AA UTG+1 with blinds at 150/300 i raise to 800 with my stack of 6000
UTG+3 (with 3.5k stack) calls rest fold flop comes K 4 K i bet out 900 he calls turn is 8 i push...
what do y'all think?
what if someone exposed a king in preflop action so you know one of them is dead? how does that change your move?