not knowing your dad one bit, or you for that matter here is my advice:

there are some people you will never be able to please, no matter what you do. thats just the way some people are sadly, they will always look for the negetives, and there is no way to change that.

I almost sold off my collection about 3 weeks ago, and im still teetering on the edge of doing it, but like people before have said, quickly liqudating assets wont help in the long run, it may help you move out of home, but if you cant afford to pay the bills etc your back to square 1

I think what you need to do, as did i to an extent is work out what is most important to you. i decided that i wanted to keep my transformer collection, but since, ive cut back on so many other things. once again ive given up drinking (yes im a heathen for saying that :P but i can easily spend over $100 in a night) ive also stemmed my impulse buying, as well as things like food at work and uni etc, and budgeting (im budgeting now for the car im going to buy in 8 months)

in the end you should look at what you think is best for you not others, because in the end you have to look out for yourself first

hope some of this helps