I also expect him to sign.
Kyle Serrano turns 22 in 3 weeks. As a fairly raw talent who still needs to learn how to throw strikes, his clock is ticking loud. If he wants to go pro, now is the time.
Negotiation 101 teaches you to talk up the availability and desirability of the options you don't want so that whoever controls the option you do want will raise the offer. That's the purpose of his comments.
MLB teams do this negotiation dozens of times per year. They're real good at seeing through the smokescreen, figuring out who really has leverage in a negotiation and maximizing their own. The Astros already have their own assessment of how likely it is that Kyle would turn down a pro opportunity now to return to UT to play for the coach who replaced his dad.
The Astros know his market value is limited by how few innings he pitched since surgery, whatever caused his departure from school, his control issues, and the fact that he won't get any money next year an an over-age senior sign.
They also know that, despite Kendall Rogers' tweet, the Brewster Whitecaps season started last night with Kyle Serrano not on the roster.
It's not likely that adds up to them paying more than double the slot value of his pick.