Hi! Thanks for the question!
Yes, taking a joint loan with your spouse and parent as a co-applicant is feasible and is allowed by the banks as it increases your repayment eligibility.
However, if the parent that you are co-applying with, has a bad credit score, it may hamper the process and may also result in the bank taking decision to increase the interest for you. Also, when you jointly take a loan, each applicant is responsible for the same. In case your father in law is not able to the amount he promises to pay, you will have the burden of it.
So, you can go for it, but it involves risk of burden and benefit of bigger amount, and you will have to weigh the advantages and dis advantages and other possibilities before takinga decision.