If, the subfloor is bad. The joist is most likely bad also. The damages can be costly since it is all hidden. This can be a big money pit. Walk away.

he said that some of the sub flooring and joists are damaged from when the home used to have termites....didn’t answer us about how extensive it is

You would be buying a pig in a poke. I would walk, too.

Not a pro. How did the inspector see the joists? From the basement? If all the damage is exposed, you could get an estimate from a contractor for new joists and subfloor and flooring. But I doubt you can guarantee that it is all exposed. I would walk away. Another house always comes up.

Subfloors can be $3-$5/sf to remove/dispose of and then replace. That does NOT include new flooring, etc. That's just the basics. When it comes to termite damage you MUST ASSUME the MOST DAMAGE is hidden. Anything that has 'wood' can and will have damage (ahem...studs in the walls, rafters, etc).

Now for the joists. The WORST CASE scenario = complete damage (no structure left to lay new subfloor down onto) = $25/sf. Several weeks/months worth of work with a BIG crew of guys going hard from sun-up to sundown. If you have a house that is 1000sf, you could be looking at $25,000 - $50,000 worth of 'fix'.

It is entirely possible (lower percentage but POSSIBLE....yay Statistics course...you saved my bacon!) that it is cheaper to tear down the house and start again. Yes this is a 'scare' tactic. It probably won't come to that, but NOW is the BEST TIME to walk away.

Ask yourself: How MUCH MONEY can I LOSE to buy a house? Do you have the FINANCES to rebuild this house? Is the price SOOOOOOO GOOD (like $80,000 under value) that you can FINANCE the fix with another mortgage without causing stress?

If $25,000 worth of work is too much for you, then walk...no RUN...away from this home. Or you have your lawyer write a caveat that has the old owner on the hook for 80% of the 'costs'. That might be the way to get the old owner to WALK AWAY from your offer.

The last two houses we bought had visible termite damage. They needed work anyway, so tearing back flooring, swapping or sistering a few joists, reframing a wall, and replacing some of the sill was pretty straightforward. I did it myself in less than a week in each case so with the significant discount that "TERMITE DAMAGE" on the report got us on the house we made out really well. In each case between what we could see and a few discreet holes in the wall (made with permission) I was able to pretty well scope out the extent of the damage and see that they had't gotten more than 8-10 feet from the entry point in any direction. If all you have to do is get in and replace damaged framing and fix drywall it's pretty easy; if they are in an expensive finished spaces like a tiled shower, or have severely compromised structure that's a whole different ball game. An ice pick or sharp screwdriver is your friend when scoping out termite damage.

Pretty much every older house, even up north in MA, has some termite damage. Running away from every one of them would leave very few choices for many home buyers around here.

This statement by the OP:

But he said that some of the sub flooring and joists are damaged from when the home used to have termites. didn’t answer us about how extensive it is or recommend that we fix the sub flooring or joists.

Leads me to believe that repairs are beyond OP's DIY skills. At a minimum, I would want to personally inspect the damage and probe around with a pocket knife to try to get an idea of how extensive the damage might be.

OP appears to be relying totally on the inspector's report. That's why I think it is in their best interest to pass. Assumption being that the OP will be paying skilled labor to make replacements & repairs.

My realtor said there are two kinds of houses in a Texas; those that have termite damage and those that will have termite damage. Still, I would walk-no, I would run away unless you can renegotiate a substantial discount. Termites can feast on a structure for years before being discovered. I have remodeled about 75% of my house and have encountered termite damage in each space but in isolated areas and in varying degrees of severity. By now I’m desensitized to any new discoveries but it still irks me that I didn’t ask for more of a discount when I bought this house.

It sounds like the termite inspector does not want to make a call about the structural stability of the house- that is fine. I presume you had a home inspection done on the property, what did they say? It is hard to know from your description (and I'm sure you don't know either) the extent of the damage- my house technically had termite damage- two 2x4's and a couple square feet of subfloor. Literally nothing to even warrant a repair. I have fixed houses where the termites made their way to the roof and the entire first floor had to be reframed as we held the house up on sticks (in my defense I told the client not to buy the house...)