To those saying 'it is all his money' - well yes in theory, but surely in marriage most normal people share their assets?
In the space of a few weeks in May/June, I got a large amount of money, low'ish 6 figures, most from my mum who had died at start of year, rest from work (employers were bought out, I had shares bought long time ago). My mum had also given me a lump sum in early 2015 (to match a similar amount given to DB a few years earlier).
I have never seen this money as just mine - yes it was my inheritence / share money, but we have been married 20 years, 2 kids, both work, have always had joint finances - why on earth would I see this as just mine?
Luckily we have no mortgage, having both bought houses young, so money is just in savings accounts for now, some short term (to then drip feed into both of our ISAs), some long term, but all in joint names.
We have things we would like to buy, a newer car for me, a van to convert into a camper (for both of us but DHs dream project), a few updates on house, but they will be joint decisions.
Op - I can understand why you feel so hurt, I really do. Yes it is probably grief talking, but I am guessing you also did a lot for MIL, so for him to cut you out of discussions totally now is awful. I dont think you are money-grabbing at all, it is not about the actual money, but the fact you are being cut out of the decision making!!
My DH supported me a lot with my mum, esp in the 16months she was housebound before she died. He made many trips to see her/do her shopping without me (2hrs each way), to allow me some breaks, and was with me on virtually every trip when we were emptying the house. I know that if I said this is my money and mine alone, no way is he getting any for his camper etc, he would accept my decision but he would also be very very hurt after all he did to support me and her.