How long should I wait for him to be ready?

I (31F) have been with my boyfriend (34M) for 2.5 years. We were close friends for about 10 years before that, so we saw each other go through chaotic previous relationships - he was engaged to someone who turned out to be a domestic abuser and a cheat (among other things). Around the same time I was in a long relationship with a guy who kept putting off commitments like getting engaged (this point is very relevent to my upcoming dilemma) and after 9 years left me for someone else, telling me he was never even interested in marriage/engagements in the first place. Now though, my bf and I do talk about everything and he knows how much commitment and marriage mean to me in a relationship. He has always said he wants to take things slow, and I shared that viewpoint at the beginning of the relationship. Over the 2.5years we have agreed that we want the same things/goals in life, and not long ago started looking into holidays abroad, talked seriously about moving in/getting a mortgage, he even mentioned a ring. But then over the span of a couple of months he began not talking about the future much at all, refused to book a holiday, just wasn't interested in looking for houses. I kept questioning him on it and he told me his mental health had taken a dive and it wasn't that he didn't want a future with me, he just didn't really see a future at all. He has struggled with depression for a long time (and so have I) so it wasn't a massive shock to me. I have been as supportive as possible, trying to link him up with a counsellor/therapist and encouraging him to work on his self-worth & self-esteem. My dilemma is that I have an impatience to get on with life. My mum died about a year ago and I'm exactly half the age she was when she died so I have this sudden motivation to get on with things I want to do. I just got a new job which will set me up better for a mortgage, and I've been having regular therapy to work on myself. I am ready to take that holiday abroad, to look at houses, to get engaged and married, maybe in a few years start a family. But it feels like my bf is at a very different stage in life and needs to figure some stuff out before moving forward in our relationship. How long do I wait for him to be ready? I am trying to be as patient and understanding as possible, but where he won't give me a timeline or any indication at all of the 'when', its so open-ended and making me worry about not only my happiness and fulfilment but the biological clock that's ticking (I'm nearly 32). Advice much appreciated, thanks in advance.