No. Affordability is distinct from eligibility, admissibility, availability and the personal consequences of permanent residence.
Use two separate decisions
Ask immigration counsel whether the route fits your circumstances and qualified financial advisers whether the proposed commitment fits your plan. A budget can show funding capacity without establishing either conclusion. Do not let the convenience of a fixed-price quote replace the review of who applies, how they qualify and what status is sought.
Run the two checks with different people, because one professional cannot verify both and a single confident answer is the thing to be suspicious of. Ask immigration counsel whether the route fits the household circumstances, addressing eligibility, admissibility, availability and the personal consequences of permanent residence. Ask a qualified financial adviser whether the proposed commitment fits the family plan.
A budget demonstrates funding capacity and establishes neither conclusion, and a fixed-price quote is convenient precisely because it makes the underlying questions invisible. Record both answers with their dates and note what each professional said fell outside their scope, since the gap between the two is where a household is unadvised. Ask each what would change their answer.
Keep both written answers together so the household can see where they disagree. Neither professional should be asked to endorse the other conclusion.