Can a veteran son co-borrow on a VA loan to help a parent qualify for more, without using his entitlement or being on title?

Yes, this works, and your son's VA entitlement stays untouched. VA entitlement is only used when a VA-guaranteed loan closes. Since you are not a veteran, your loan would be conventional or another non-VA program, and a veteran co-borrowing on a non-VA loan uses none of his guaranty. Your son can add his income and credit to help you qualify for more, without being on title, and his entitlement stays free for his own purchase later. One detail matters for his future. When your son applies for his own mortgage, the co-signed loan shows up as his debt too, which could limit what he qualifies for. There is a clean way to exclude that payment from his debt-to-income ratio: document that someone else makes the payment, typically with the most recent 12 months of canceled checks or bank statements showing the payment coming from an account he is not on, with no late payments in that stretch. Keep clean records from day one so the proof is easy to produce when the time comes. Co-borrower requirements and the exact exclusion rules vary a bit by loan type and can change, so confirm the current rules for the specific program you use. If you want, we can structure the purchase so it helps you qualify now without complicating your son's own purchase down the road.