Replying to Boots and Bunions

Tldr; my dad has bunions. Won't get surgery. Will cheap boots and boot work do any good?

My dad has awful bunions. I'm talking probably about 2cm out. Last time he went skiing, he used rental boots and they were rubbed raw and were nasty open wounds for a month. Because of that he's hesitant to ski and also stubborn and won't just get surgery to remove them. His ability level is beginner-intermediate if I had to judge so he goes pretty easy on the slopes. Because he's so conservative with skiing, I'm not too concerned that having too big or soft boot will have any negative meaningful difference in his skiing satisfaction. Comfort over performance in this scenario.

My question to you folks is would it be worthwhile to get a cheapo pair of beginner boots on sale and get the sides punched out as far as they'll go? I know they prob can't go that far, but anything is better than rentals. My local ski shop does free boot work on their boots and they have some really cheap beginner boots on sale. Like $120-140. I have an extra pair of skis (with adjustable bindings) so could literally pay for itself in 5 days of skiing (vs rentals). The cheapest boots are Dabello mx65.