I can certainly give it a go! I'm a physio student so lots of study of movement and biomechanics etc.
So putting aside the whole 'alien' thing for a moment, I believe theoretically yes it's body could have supported the large head.
This would have been dependent on several variables, including muscle mass, muscle tone, motor and sensorimotor control - in other words how its nervous system communicated with its muscles to coordinate the sequencing and timing of muscle activity - all of these things would contribute to overcoming the weight and mechanical disadvantages of a very large head in proportion to a small body in order to achieve postural control and balance.
How it moved and walked is another major factor, including whether it was bipedal/quadrupedal; it may have needed to move in a compensatory way in order to readjust it's centre of gravity and widen its base of support due to the large head - which appears to protrude more at the back, and small body and feet in comparison.
Lastly, lets suppose for a moment that it is an ancient extra-terrestrial being that evolved on a distant planet. How much it would need to compensate for the larger head would be dependent on how much gravity there was on that planet, and possibly other variations in the laws of physics I suppose.
I hope that helps, obviously only meant to be a bit of fun, definitely not any kind of theoretical, alien movement, head expert 😂